annotation_CSV/PMC4980666.csv

anno_start	anno_end	anno_text	entity_type	sentence	section
0	15	N-acylhydrazone	chemical	N-acylhydrazone inhibitors of influenza virus PA endonuclease with versatile metal binding modes	TITLE
30	39	influenza	taxonomy_domain	N-acylhydrazone inhibitors of influenza virus PA endonuclease with versatile metal binding modes	TITLE
40	45	virus	taxonomy_domain	N-acylhydrazone inhibitors of influenza virus PA endonuclease with versatile metal binding modes	TITLE
46	48	PA	protein	N-acylhydrazone inhibitors of influenza virus PA endonuclease with versatile metal binding modes	TITLE
49	61	endonuclease	protein_type	N-acylhydrazone inhibitors of influenza virus PA endonuclease with versatile metal binding modes	TITLE
0	9	Influenza	taxonomy_domain	Influenza virus PA endonuclease has recently emerged as an attractive target for the development of novel antiviral therapeutics.	ABSTRACT
10	15	virus	taxonomy_domain	Influenza virus PA endonuclease has recently emerged as an attractive target for the development of novel antiviral therapeutics.	ABSTRACT
16	18	PA	protein	Influenza virus PA endonuclease has recently emerged as an attractive target for the development of novel antiviral therapeutics.	ABSTRACT
19	31	endonuclease	protein_type	Influenza virus PA endonuclease has recently emerged as an attractive target for the development of novel antiviral therapeutics.	ABSTRACT
46	50	Mg2+	chemical	This is an enzyme with divalent metal ion(s) (Mg2+ or Mn2+) in its catalytic site: chelation of these metal cofactors is an attractive strategy to inhibit enzymatic activity.	ABSTRACT
54	58	Mn2+	chemical	This is an enzyme with divalent metal ion(s) (Mg2+ or Mn2+) in its catalytic site: chelation of these metal cofactors is an attractive strategy to inhibit enzymatic activity.	ABSTRACT
67	81	catalytic site	site	This is an enzyme with divalent metal ion(s) (Mg2+ or Mn2+) in its catalytic site: chelation of these metal cofactors is an attractive strategy to inhibit enzymatic activity.	ABSTRACT
83	92	chelation	bond_interaction	This is an enzyme with divalent metal ion(s) (Mg2+ or Mn2+) in its catalytic site: chelation of these metal cofactors is an attractive strategy to inhibit enzymatic activity.	ABSTRACT
43	59	N-acylhydrazones	chemical	Here we report the activity of a series of N-acylhydrazones in an enzymatic assay with PA-Nter endonuclease, as well as in cell-based influenza vRNP reconstitution and virus yield assays.	ABSTRACT
66	81	enzymatic assay	experimental_method	Here we report the activity of a series of N-acylhydrazones in an enzymatic assay with PA-Nter endonuclease, as well as in cell-based influenza vRNP reconstitution and virus yield assays.	ABSTRACT
87	89	PA	protein	Here we report the activity of a series of N-acylhydrazones in an enzymatic assay with PA-Nter endonuclease, as well as in cell-based influenza vRNP reconstitution and virus yield assays.	ABSTRACT
90	94	Nter	structure_element	Here we report the activity of a series of N-acylhydrazones in an enzymatic assay with PA-Nter endonuclease, as well as in cell-based influenza vRNP reconstitution and virus yield assays.	ABSTRACT
95	107	endonuclease	protein_type	Here we report the activity of a series of N-acylhydrazones in an enzymatic assay with PA-Nter endonuclease, as well as in cell-based influenza vRNP reconstitution and virus yield assays.	ABSTRACT
123	163	cell-based influenza vRNP reconstitution	experimental_method	Here we report the activity of a series of N-acylhydrazones in an enzymatic assay with PA-Nter endonuclease, as well as in cell-based influenza vRNP reconstitution and virus yield assays.	ABSTRACT
168	186	virus yield assays	experimental_method	Here we report the activity of a series of N-acylhydrazones in an enzymatic assay with PA-Nter endonuclease, as well as in cell-based influenza vRNP reconstitution and virus yield assays.	ABSTRACT
8	24	N-acylhydrazones	chemical	Several N-acylhydrazones were found to have promising anti-influenza activity in the low micromolar concentration range and good selectivity.	ABSTRACT
59	68	influenza	taxonomy_domain	Several N-acylhydrazones were found to have promising anti-influenza activity in the low micromolar concentration range and good selectivity.	ABSTRACT
0	29	Computational docking studies	experimental_method	Computational docking studies are carried on to investigate the key features that determine inhibition of the endonuclease enzyme by N-acylhydrazones.	ABSTRACT
110	122	endonuclease	protein_type	Computational docking studies are carried on to investigate the key features that determine inhibition of the endonuclease enzyme by N-acylhydrazones.	ABSTRACT
133	149	N-acylhydrazones	chemical	Computational docking studies are carried on to investigate the key features that determine inhibition of the endonuclease enzyme by N-acylhydrazones.	ABSTRACT
31	48	crystal structure	evidence	Moreover, we here describe the crystal structure of PA-Nter in complex with one of the most active inhibitors, revealing its interactions within the protein’s active site.	ABSTRACT
52	54	PA	protein	Moreover, we here describe the crystal structure of PA-Nter in complex with one of the most active inhibitors, revealing its interactions within the protein’s active site.	ABSTRACT
55	59	Nter	structure_element	Moreover, we here describe the crystal structure of PA-Nter in complex with one of the most active inhibitors, revealing its interactions within the protein’s active site.	ABSTRACT
60	75	in complex with	protein_state	Moreover, we here describe the crystal structure of PA-Nter in complex with one of the most active inhibitors, revealing its interactions within the protein’s active site.	ABSTRACT
159	170	active site	site	Moreover, we here describe the crystal structure of PA-Nter in complex with one of the most active inhibitors, revealing its interactions within the protein’s active site.	ABSTRACT
0	9	Influenza	taxonomy_domain	Influenza virus is an enveloped virus with a segmented negative-oriented single-stranded RNA genome, belonging to the Orthomyxoviridae.	INTRO
10	15	virus	taxonomy_domain	Influenza virus is an enveloped virus with a segmented negative-oriented single-stranded RNA genome, belonging to the Orthomyxoviridae.	INTRO
22	37	enveloped virus	taxonomy_domain	Influenza virus is an enveloped virus with a segmented negative-oriented single-stranded RNA genome, belonging to the Orthomyxoviridae.	INTRO
55	92	negative-oriented single-stranded RNA	chemical	Influenza virus is an enveloped virus with a segmented negative-oriented single-stranded RNA genome, belonging to the Orthomyxoviridae.	INTRO
118	134	Orthomyxoviridae	taxonomy_domain	Influenza virus is an enveloped virus with a segmented negative-oriented single-stranded RNA genome, belonging to the Orthomyxoviridae.	INTRO
9	20	influenza A	taxonomy_domain	Seasonal influenza A and B viruses affect each year approximately 5–10% of the adult and 20–30% of the paediatric population, and there is a permanent risk of sudden influenza pandemics, such as the notorious ‘Spanish flu’ in 1918 and the swine-origin H1N1 pandemic in 2009.	INTRO
25	26	B	taxonomy_domain	Seasonal influenza A and B viruses affect each year approximately 5–10% of the adult and 20–30% of the paediatric population, and there is a permanent risk of sudden influenza pandemics, such as the notorious ‘Spanish flu’ in 1918 and the swine-origin H1N1 pandemic in 2009.	INTRO
27	34	viruses	taxonomy_domain	Seasonal influenza A and B viruses affect each year approximately 5–10% of the adult and 20–30% of the paediatric population, and there is a permanent risk of sudden influenza pandemics, such as the notorious ‘Spanish flu’ in 1918 and the swine-origin H1N1 pandemic in 2009.	INTRO
166	175	influenza	taxonomy_domain	Seasonal influenza A and B viruses affect each year approximately 5–10% of the adult and 20–30% of the paediatric population, and there is a permanent risk of sudden influenza pandemics, such as the notorious ‘Spanish flu’ in 1918 and the swine-origin H1N1 pandemic in 2009.	INTRO
252	256	H1N1	species	Seasonal influenza A and B viruses affect each year approximately 5–10% of the adult and 20–30% of the paediatric population, and there is a permanent risk of sudden influenza pandemics, such as the notorious ‘Spanish flu’ in 1918 and the swine-origin H1N1 pandemic in 2009.	INTRO
20	29	influenza	taxonomy_domain	Two classes of anti-influenza virus drugs are available, acting on the viral M2 ion-channel (amantadine and rimantadine) or on the viral neuraminidase (zanamivir and oseltamivir).	INTRO
30	35	virus	taxonomy_domain	Two classes of anti-influenza virus drugs are available, acting on the viral M2 ion-channel (amantadine and rimantadine) or on the viral neuraminidase (zanamivir and oseltamivir).	INTRO
71	76	viral	taxonomy_domain	Two classes of anti-influenza virus drugs are available, acting on the viral M2 ion-channel (amantadine and rimantadine) or on the viral neuraminidase (zanamivir and oseltamivir).	INTRO
77	91	M2 ion-channel	protein_type	Two classes of anti-influenza virus drugs are available, acting on the viral M2 ion-channel (amantadine and rimantadine) or on the viral neuraminidase (zanamivir and oseltamivir).	INTRO
93	103	amantadine	chemical	Two classes of anti-influenza virus drugs are available, acting on the viral M2 ion-channel (amantadine and rimantadine) or on the viral neuraminidase (zanamivir and oseltamivir).	INTRO
108	119	rimantadine	chemical	Two classes of anti-influenza virus drugs are available, acting on the viral M2 ion-channel (amantadine and rimantadine) or on the viral neuraminidase (zanamivir and oseltamivir).	INTRO
131	136	viral	taxonomy_domain	Two classes of anti-influenza virus drugs are available, acting on the viral M2 ion-channel (amantadine and rimantadine) or on the viral neuraminidase (zanamivir and oseltamivir).	INTRO
137	150	neuraminidase	protein_type	Two classes of anti-influenza virus drugs are available, acting on the viral M2 ion-channel (amantadine and rimantadine) or on the viral neuraminidase (zanamivir and oseltamivir).	INTRO
152	161	zanamivir	chemical	Two classes of anti-influenza virus drugs are available, acting on the viral M2 ion-channel (amantadine and rimantadine) or on the viral neuraminidase (zanamivir and oseltamivir).	INTRO
166	177	oseltamivir	chemical	Two classes of anti-influenza virus drugs are available, acting on the viral M2 ion-channel (amantadine and rimantadine) or on the viral neuraminidase (zanamivir and oseltamivir).	INTRO
4	6	M2	protein_type	The M2 inhibitors have limited clinical utility due to their central nervous system side effects and widespread resistance, as in the case of the 2009 pandemic H1N1 virus; resistance is also a growing concern for oseltamivir.	INTRO
160	164	H1N1	species	The M2 inhibitors have limited clinical utility due to their central nervous system side effects and widespread resistance, as in the case of the 2009 pandemic H1N1 virus; resistance is also a growing concern for oseltamivir.	INTRO
165	170	virus	taxonomy_domain	The M2 inhibitors have limited clinical utility due to their central nervous system side effects and widespread resistance, as in the case of the 2009 pandemic H1N1 virus; resistance is also a growing concern for oseltamivir.	INTRO
213	224	oseltamivir	chemical	The M2 inhibitors have limited clinical utility due to their central nervous system side effects and widespread resistance, as in the case of the 2009 pandemic H1N1 virus; resistance is also a growing concern for oseltamivir.	INTRO
4	13	influenza	taxonomy_domain	The influenza virus polymerase complex is composed of three subunits: PB1, PB2 and PA.	INTRO
14	19	virus	taxonomy_domain	The influenza virus polymerase complex is composed of three subunits: PB1, PB2 and PA.	INTRO
20	30	polymerase	protein_type	The influenza virus polymerase complex is composed of three subunits: PB1, PB2 and PA.	INTRO
70	73	PB1	protein	The influenza virus polymerase complex is composed of three subunits: PB1, PB2 and PA.	INTRO
75	78	PB2	protein	The influenza virus polymerase complex is composed of three subunits: PB1, PB2 and PA.	INTRO
83	85	PA	protein	The influenza virus polymerase complex is composed of three subunits: PB1, PB2 and PA.	INTRO
4	6	PA	protein	The PA subunit performs the ‘cap-snatching’ endonuclease reaction, the PB2 subunit is responsible for initial binding of the capped RNAs, while the actual RNA synthesis is performed by the PB1 protein.	INTRO
7	14	subunit	structure_element	The PA subunit performs the ‘cap-snatching’ endonuclease reaction, the PB2 subunit is responsible for initial binding of the capped RNAs, while the actual RNA synthesis is performed by the PB1 protein.	INTRO
44	56	endonuclease	protein_type	The PA subunit performs the ‘cap-snatching’ endonuclease reaction, the PB2 subunit is responsible for initial binding of the capped RNAs, while the actual RNA synthesis is performed by the PB1 protein.	INTRO
71	74	PB2	protein	The PA subunit performs the ‘cap-snatching’ endonuclease reaction, the PB2 subunit is responsible for initial binding of the capped RNAs, while the actual RNA synthesis is performed by the PB1 protein.	INTRO
75	82	subunit	structure_element	The PA subunit performs the ‘cap-snatching’ endonuclease reaction, the PB2 subunit is responsible for initial binding of the capped RNAs, while the actual RNA synthesis is performed by the PB1 protein.	INTRO
125	136	capped RNAs	chemical	The PA subunit performs the ‘cap-snatching’ endonuclease reaction, the PB2 subunit is responsible for initial binding of the capped RNAs, while the actual RNA synthesis is performed by the PB1 protein.	INTRO
155	158	RNA	chemical	The PA subunit performs the ‘cap-snatching’ endonuclease reaction, the PB2 subunit is responsible for initial binding of the capped RNAs, while the actual RNA synthesis is performed by the PB1 protein.	INTRO
189	192	PB1	protein	The PA subunit performs the ‘cap-snatching’ endonuclease reaction, the PB2 subunit is responsible for initial binding of the capped RNAs, while the actual RNA synthesis is performed by the PB1 protein.	INTRO
30	35	viral	taxonomy_domain	Given its crucial role in the viral life cycle, the influenza virus polymerase is widely recognized as a superior target for antiviral drug development and, in particular, inhibition of the PA endonuclease has deserved much attention in recent years.	INTRO
52	61	influenza	taxonomy_domain	Given its crucial role in the viral life cycle, the influenza virus polymerase is widely recognized as a superior target for antiviral drug development and, in particular, inhibition of the PA endonuclease has deserved much attention in recent years.	INTRO
62	67	virus	taxonomy_domain	Given its crucial role in the viral life cycle, the influenza virus polymerase is widely recognized as a superior target for antiviral drug development and, in particular, inhibition of the PA endonuclease has deserved much attention in recent years.	INTRO
68	78	polymerase	protein_type	Given its crucial role in the viral life cycle, the influenza virus polymerase is widely recognized as a superior target for antiviral drug development and, in particular, inhibition of the PA endonuclease has deserved much attention in recent years.	INTRO
190	192	PA	protein	Given its crucial role in the viral life cycle, the influenza virus polymerase is widely recognized as a superior target for antiviral drug development and, in particular, inhibition of the PA endonuclease has deserved much attention in recent years.	INTRO
193	205	endonuclease	protein_type	Given its crucial role in the viral life cycle, the influenza virus polymerase is widely recognized as a superior target for antiviral drug development and, in particular, inhibition of the PA endonuclease has deserved much attention in recent years.	INTRO
4	16	endonuclease	protein_type	The endonuclease catalytic site resides in the N-terminal domain of PA (PA-Nter; residues 1~195).	INTRO
17	31	catalytic site	site	The endonuclease catalytic site resides in the N-terminal domain of PA (PA-Nter; residues 1~195).	INTRO
47	64	N-terminal domain	structure_element	The endonuclease catalytic site resides in the N-terminal domain of PA (PA-Nter; residues 1~195).	INTRO
68	70	PA	protein	The endonuclease catalytic site resides in the N-terminal domain of PA (PA-Nter; residues 1~195).	INTRO
72	74	PA	protein	The endonuclease catalytic site resides in the N-terminal domain of PA (PA-Nter; residues 1~195).	INTRO
75	79	Nter	structure_element	The endonuclease catalytic site resides in the N-terminal domain of PA (PA-Nter; residues 1~195).	INTRO
90	95	1~195	residue_range	The endonuclease catalytic site resides in the N-terminal domain of PA (PA-Nter; residues 1~195).	INTRO
15	24	histidine	residue_name	It comprises a histidine (His41) and a cluster of three strictly conserved acidic residues (Glu80, Asp108, Glu119), which coordinate (together with Ile120) one, two, or three manganese or magnesium ions.	INTRO
26	31	His41	residue_name_number	It comprises a histidine (His41) and a cluster of three strictly conserved acidic residues (Glu80, Asp108, Glu119), which coordinate (together with Ile120) one, two, or three manganese or magnesium ions.	INTRO
56	74	strictly conserved	protein_state	It comprises a histidine (His41) and a cluster of three strictly conserved acidic residues (Glu80, Asp108, Glu119), which coordinate (together with Ile120) one, two, or three manganese or magnesium ions.	INTRO
75	81	acidic	protein_state	It comprises a histidine (His41) and a cluster of three strictly conserved acidic residues (Glu80, Asp108, Glu119), which coordinate (together with Ile120) one, two, or three manganese or magnesium ions.	INTRO
92	97	Glu80	residue_name_number	It comprises a histidine (His41) and a cluster of three strictly conserved acidic residues (Glu80, Asp108, Glu119), which coordinate (together with Ile120) one, two, or three manganese or magnesium ions.	INTRO
99	105	Asp108	residue_name_number	It comprises a histidine (His41) and a cluster of three strictly conserved acidic residues (Glu80, Asp108, Glu119), which coordinate (together with Ile120) one, two, or three manganese or magnesium ions.	INTRO
107	113	Glu119	residue_name_number	It comprises a histidine (His41) and a cluster of three strictly conserved acidic residues (Glu80, Asp108, Glu119), which coordinate (together with Ile120) one, two, or three manganese or magnesium ions.	INTRO
122	132	coordinate	bond_interaction	It comprises a histidine (His41) and a cluster of three strictly conserved acidic residues (Glu80, Asp108, Glu119), which coordinate (together with Ile120) one, two, or three manganese or magnesium ions.	INTRO
148	154	Ile120	residue_name_number	It comprises a histidine (His41) and a cluster of three strictly conserved acidic residues (Glu80, Asp108, Glu119), which coordinate (together with Ile120) one, two, or three manganese or magnesium ions.	INTRO
175	184	manganese	chemical	It comprises a histidine (His41) and a cluster of three strictly conserved acidic residues (Glu80, Asp108, Glu119), which coordinate (together with Ile120) one, two, or three manganese or magnesium ions.	INTRO
188	197	magnesium	chemical	It comprises a histidine (His41) and a cluster of three strictly conserved acidic residues (Glu80, Asp108, Glu119), which coordinate (together with Ile120) one, two, or three manganese or magnesium ions.	INTRO
41	45	Mg2+	chemical	Since the intracellular concentration of Mg2+ is at least 1000-fold higher than that of Mn2+, magnesium may be more biologically relevant.	INTRO
88	93	Mn2+,	chemical	Since the intracellular concentration of Mg2+ is at least 1000-fold higher than that of Mn2+, magnesium may be more biologically relevant.	INTRO
94	103	magnesium	chemical	Since the intracellular concentration of Mg2+ is at least 1000-fold higher than that of Mn2+, magnesium may be more biologically relevant.	INTRO
70	81	active site	site	A controversy about number and type of metal ions exists also for the active site of HIV-1 integrase.	INTRO
85	90	HIV-1	species	A controversy about number and type of metal ions exists also for the active site of HIV-1 integrase.	INTRO
91	100	integrase	protein_type	A controversy about number and type of metal ions exists also for the active site of HIV-1 integrase.	INTRO
0	5	HIV-1	species	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
6	15	integrase	protein_type	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
113	118	metal	chemical	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
134	139	viral	taxonomy_domain	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
168	170	PA	protein	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
242	251	influenza	taxonomy_domain	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
252	264	endonuclease	protein_type	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
296	318	2,4-dioxobutanoic acid	chemical	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
332	341	flutimide	chemical	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
363	384	2-hydroxyphenyl amide	chemical	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
409	423	tetramic acids	chemical	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
425	449	5-hydroxypyrimidin-4-one	chemical	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
463	474	marchantins	chemical	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
479	488	green tea	taxonomy_domain	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
489	498	catechins	chemical	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
505	531	epigallocatechin-3-gallate	chemical	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
533	537	EGCG	chemical	HIV-1 integrase inhibitors are a paradigm for the innovative drug concept that is based on coordination with the metal cofactor(s) of viral enzymes: similarly, several PA-binding agents with metal-chelating properties have been identified as influenza endonuclease inhibitors (Fig. 1), including 2,4-dioxobutanoic acid derivatives, flutimide and its derivatives, 2-hydroxyphenyl amide derivatives, as well as tetramic acids, 5-hydroxypyrimidin-4-one derivatives, marchantins and green tea catechins, like epigallocatechin-3-gallate (EGCG, Fig. 1).	INTRO
102	104	PA	protein	In recent years, we focused our research on chemical scaffolds that are able to chelate metal ions of PA-Nter, resulting in inhibition of influenza virus replication.	INTRO
105	109	Nter	structure_element	In recent years, we focused our research on chemical scaffolds that are able to chelate metal ions of PA-Nter, resulting in inhibition of influenza virus replication.	INTRO
138	147	influenza	taxonomy_domain	In recent years, we focused our research on chemical scaffolds that are able to chelate metal ions of PA-Nter, resulting in inhibition of influenza virus replication.	INTRO
148	153	virus	taxonomy_domain	In recent years, we focused our research on chemical scaffolds that are able to chelate metal ions of PA-Nter, resulting in inhibition of influenza virus replication.	INTRO
0	16	N-acylhydrazones	chemical	N-acylhydrazones represent an appealing class of chelating ligands with a broad spectrum of biological activities, such as activity against HIV, hepatitis A, vaccinia and influenza virus.	INTRO
80	88	spectrum	evidence	N-acylhydrazones represent an appealing class of chelating ligands with a broad spectrum of biological activities, such as activity against HIV, hepatitis A, vaccinia and influenza virus.	INTRO
140	143	HIV	taxonomy_domain	N-acylhydrazones represent an appealing class of chelating ligands with a broad spectrum of biological activities, such as activity against HIV, hepatitis A, vaccinia and influenza virus.	INTRO
145	156	hepatitis A	taxonomy_domain	N-acylhydrazones represent an appealing class of chelating ligands with a broad spectrum of biological activities, such as activity against HIV, hepatitis A, vaccinia and influenza virus.	INTRO
158	166	vaccinia	taxonomy_domain	N-acylhydrazones represent an appealing class of chelating ligands with a broad spectrum of biological activities, such as activity against HIV, hepatitis A, vaccinia and influenza virus.	INTRO
171	180	influenza	taxonomy_domain	N-acylhydrazones represent an appealing class of chelating ligands with a broad spectrum of biological activities, such as activity against HIV, hepatitis A, vaccinia and influenza virus.	INTRO
181	186	virus	taxonomy_domain	N-acylhydrazones represent an appealing class of chelating ligands with a broad spectrum of biological activities, such as activity against HIV, hepatitis A, vaccinia and influenza virus.	INTRO
70	86	N-acylhydrazones	chemical	In the present work, we report the biological activity of a series of N-acylhydrazones (Fig. 2), as determined in an enzymatic assay with PA-Nter endonuclease as well as in cell-based influenza viral ribonucleoprotein (vRNP) reconstitution and virus yield assays.	INTRO
117	132	enzymatic assay	experimental_method	In the present work, we report the biological activity of a series of N-acylhydrazones (Fig. 2), as determined in an enzymatic assay with PA-Nter endonuclease as well as in cell-based influenza viral ribonucleoprotein (vRNP) reconstitution and virus yield assays.	INTRO
138	140	PA	protein	In the present work, we report the biological activity of a series of N-acylhydrazones (Fig. 2), as determined in an enzymatic assay with PA-Nter endonuclease as well as in cell-based influenza viral ribonucleoprotein (vRNP) reconstitution and virus yield assays.	INTRO
141	145	Nter	structure_element	In the present work, we report the biological activity of a series of N-acylhydrazones (Fig. 2), as determined in an enzymatic assay with PA-Nter endonuclease as well as in cell-based influenza viral ribonucleoprotein (vRNP) reconstitution and virus yield assays.	INTRO
146	158	endonuclease	protein_type	In the present work, we report the biological activity of a series of N-acylhydrazones (Fig. 2), as determined in an enzymatic assay with PA-Nter endonuclease as well as in cell-based influenza viral ribonucleoprotein (vRNP) reconstitution and virus yield assays.	INTRO
173	239	cell-based influenza viral ribonucleoprotein (vRNP) reconstitution	experimental_method	In the present work, we report the biological activity of a series of N-acylhydrazones (Fig. 2), as determined in an enzymatic assay with PA-Nter endonuclease as well as in cell-based influenza viral ribonucleoprotein (vRNP) reconstitution and virus yield assays.	INTRO
244	262	virus yield assays	experimental_method	In the present work, we report the biological activity of a series of N-acylhydrazones (Fig. 2), as determined in an enzymatic assay with PA-Nter endonuclease as well as in cell-based influenza viral ribonucleoprotein (vRNP) reconstitution and virus yield assays.	INTRO
8	24	N-acylhydrazones	chemical	Several N-acylhydrazones were found to have promising anti-influenza activity with 50% effective concentration values (EC50) in the range of 3–20 μM and good selectivity (Table 1 and Fig. 3).	INTRO
59	68	influenza	taxonomy_domain	Several N-acylhydrazones were found to have promising anti-influenza activity with 50% effective concentration values (EC50) in the range of 3–20 μM and good selectivity (Table 1 and Fig. 3).	INTRO
83	110	50% effective concentration	evidence	Several N-acylhydrazones were found to have promising anti-influenza activity with 50% effective concentration values (EC50) in the range of 3–20 μM and good selectivity (Table 1 and Fig. 3).	INTRO
119	123	EC50	evidence	Several N-acylhydrazones were found to have promising anti-influenza activity with 50% effective concentration values (EC50) in the range of 3–20 μM and good selectivity (Table 1 and Fig. 3).	INTRO
0	29	Computational docking studies	experimental_method	Computational docking studies of two candidate ligands in the PA-Nter active site gave information about the features that could determine inhibition of endonuclease activity.	INTRO
62	64	PA	protein	Computational docking studies of two candidate ligands in the PA-Nter active site gave information about the features that could determine inhibition of endonuclease activity.	INTRO
65	69	Nter	structure_element	Computational docking studies of two candidate ligands in the PA-Nter active site gave information about the features that could determine inhibition of endonuclease activity.	INTRO
70	81	active site	site	Computational docking studies of two candidate ligands in the PA-Nter active site gave information about the features that could determine inhibition of endonuclease activity.	INTRO
153	165	endonuclease	protein_type	Computational docking studies of two candidate ligands in the PA-Nter active site gave information about the features that could determine inhibition of endonuclease activity.	INTRO
26	49	X-ray crystal structure	evidence	Moreover, we describe the X-ray crystal structure of PA-Nter in complex with one of the most active inhibitors.	INTRO
53	55	PA	protein	Moreover, we describe the X-ray crystal structure of PA-Nter in complex with one of the most active inhibitors.	INTRO
56	60	Nter	structure_element	Moreover, we describe the X-ray crystal structure of PA-Nter in complex with one of the most active inhibitors.	INTRO
61	76	in complex with	protein_state	Moreover, we describe the X-ray crystal structure of PA-Nter in complex with one of the most active inhibitors.	INTRO
0	16	N-acylhydrazones	chemical	N-acylhydrazones 1–27 (Fig. 2) were prepared in high yields by following literature methods (Fig. 2A); they were characterized by spectroscopic tools, mass spectrometry and elemental analysis.	RESULTS
17	21	1–27	chemical	N-acylhydrazones 1–27 (Fig. 2) were prepared in high yields by following literature methods (Fig. 2A); they were characterized by spectroscopic tools, mass spectrometry and elemental analysis.	RESULTS
151	168	mass spectrometry	experimental_method	N-acylhydrazones 1–27 (Fig. 2) were prepared in high yields by following literature methods (Fig. 2A); they were characterized by spectroscopic tools, mass spectrometry and elemental analysis.	RESULTS
173	191	elemental analysis	experimental_method	N-acylhydrazones 1–27 (Fig. 2) were prepared in high yields by following literature methods (Fig. 2A); they were characterized by spectroscopic tools, mass spectrometry and elemental analysis.	RESULTS
53	57	1–27	chemical	Even if isomerism around the C = N bond is possible, 1–27 are present in the E form in solution, as evidenced by the chemical shift values of the HC = N and NH protons in the 1H-NMR spectrum.	RESULTS
175	181	1H-NMR	experimental_method	Even if isomerism around the C = N bond is possible, 1–27 are present in the E form in solution, as evidenced by the chemical shift values of the HC = N and NH protons in the 1H-NMR spectrum.	RESULTS
182	190	spectrum	evidence	Even if isomerism around the C = N bond is possible, 1–27 are present in the E form in solution, as evidenced by the chemical shift values of the HC = N and NH protons in the 1H-NMR spectrum.	RESULTS
52	53	3	chemical	Exceptions are represented by the alkyl-derivatives 3 and 4 (2:1 and 5:3 E:Z ratio, respectively).	RESULTS
58	59	4	chemical	Exceptions are represented by the alkyl-derivatives 3 and 4 (2:1 and 5:3 E:Z ratio, respectively).	RESULTS
74	88	acylhydrazones	chemical	If R’ (Fig. 2A) is a 2-hydroxy substituted phenyl ring, the corresponding acylhydrazones can coordinate one or, depending on denticity, two metal centers (modes A and B in Fig. 4).	RESULTS
93	103	coordinate	bond_interaction	If R’ (Fig. 2A) is a 2-hydroxy substituted phenyl ring, the corresponding acylhydrazones can coordinate one or, depending on denticity, two metal centers (modes A and B in Fig. 4).	RESULTS
14	57	N’-(2,3-dihydroxybenzylidene)-semicarbazide	chemical	Starting from N’-(2,3-dihydroxybenzylidene)-semicarbazide (1) and its methoxy-analogue (2), we modified the acylhydrazonic substituent R” (3–8, 18, 19, Fig. 2A).	RESULTS
59	60	1	chemical	Starting from N’-(2,3-dihydroxybenzylidene)-semicarbazide (1) and its methoxy-analogue (2), we modified the acylhydrazonic substituent R” (3–8, 18, 19, Fig. 2A).	RESULTS
88	89	2	chemical	Starting from N’-(2,3-dihydroxybenzylidene)-semicarbazide (1) and its methoxy-analogue (2), we modified the acylhydrazonic substituent R” (3–8, 18, 19, Fig. 2A).	RESULTS
139	142	3–8	chemical	Starting from N’-(2,3-dihydroxybenzylidene)-semicarbazide (1) and its methoxy-analogue (2), we modified the acylhydrazonic substituent R” (3–8, 18, 19, Fig. 2A).	RESULTS
144	146	18	chemical	Starting from N’-(2,3-dihydroxybenzylidene)-semicarbazide (1) and its methoxy-analogue (2), we modified the acylhydrazonic substituent R” (3–8, 18, 19, Fig. 2A).	RESULTS
148	150	19	chemical	Starting from N’-(2,3-dihydroxybenzylidene)-semicarbazide (1) and its methoxy-analogue (2), we modified the acylhydrazonic substituent R” (3–8, 18, 19, Fig. 2A).	RESULTS
3	5	18	chemical	In 18 and 19, also the gallic moiety can be involved in the chelation of the metal cofactors (mode C, Fig. 4).	RESULTS
10	12	19	chemical	In 18 and 19, also the gallic moiety can be involved in the chelation of the metal cofactors (mode C, Fig. 4).	RESULTS
23	29	gallic	chemical	In 18 and 19, also the gallic moiety can be involved in the chelation of the metal cofactors (mode C, Fig. 4).	RESULTS
60	69	chelation	bond_interaction	In 18 and 19, also the gallic moiety can be involved in the chelation of the metal cofactors (mode C, Fig. 4).	RESULTS
58	62	9–11	chemical	In order to investigate the role of hydroxyl substituents 9–11, 13–17, 20–23 and 27 were also synthesized.	RESULTS
64	69	13–17	chemical	In order to investigate the role of hydroxyl substituents 9–11, 13–17, 20–23 and 27 were also synthesized.	RESULTS
71	76	20–23	chemical	In order to investigate the role of hydroxyl substituents 9–11, 13–17, 20–23 and 27 were also synthesized.	RESULTS
81	83	27	chemical	In order to investigate the role of hydroxyl substituents 9–11, 13–17, 20–23 and 27 were also synthesized.	RESULTS
9	11	12	chemical	Compound 12 was synthesized in order to confirm the crucial influence of the gallic moiety.	RESULTS
77	83	gallic	chemical	Compound 12 was synthesized in order to confirm the crucial influence of the gallic moiety.	RESULTS
9	11	26	chemical	Finally, 26 was here considered, because it is an inhibitor of HIV RNase H, another enzyme with two magnesium ions in its active site.	RESULTS
63	66	HIV	taxonomy_domain	Finally, 26 was here considered, because it is an inhibitor of HIV RNase H, another enzyme with two magnesium ions in its active site.	RESULTS
67	74	RNase H	protein	Finally, 26 was here considered, because it is an inhibitor of HIV RNase H, another enzyme with two magnesium ions in its active site.	RESULTS
100	109	magnesium	chemical	Finally, 26 was here considered, because it is an inhibitor of HIV RNase H, another enzyme with two magnesium ions in its active site.	RESULTS
122	133	active site	site	Finally, 26 was here considered, because it is an inhibitor of HIV RNase H, another enzyme with two magnesium ions in its active site.	RESULTS
37	53	N-acylhydrazones	chemical	Since the inhibitory activity of the N-acylhydrazones could be related to chelation of the divalent metal cofactor(s) in the influenza PA-Nter active site, we investigated the coordination properties of one model ligand (i.e. 19, H2L) towards Mg2+.	RESULTS
74	83	chelation	bond_interaction	Since the inhibitory activity of the N-acylhydrazones could be related to chelation of the divalent metal cofactor(s) in the influenza PA-Nter active site, we investigated the coordination properties of one model ligand (i.e. 19, H2L) towards Mg2+.	RESULTS
100	105	metal	chemical	Since the inhibitory activity of the N-acylhydrazones could be related to chelation of the divalent metal cofactor(s) in the influenza PA-Nter active site, we investigated the coordination properties of one model ligand (i.e. 19, H2L) towards Mg2+.	RESULTS
125	134	influenza	taxonomy_domain	Since the inhibitory activity of the N-acylhydrazones could be related to chelation of the divalent metal cofactor(s) in the influenza PA-Nter active site, we investigated the coordination properties of one model ligand (i.e. 19, H2L) towards Mg2+.	RESULTS
135	137	PA	protein	Since the inhibitory activity of the N-acylhydrazones could be related to chelation of the divalent metal cofactor(s) in the influenza PA-Nter active site, we investigated the coordination properties of one model ligand (i.e. 19, H2L) towards Mg2+.	RESULTS
138	142	Nter	structure_element	Since the inhibitory activity of the N-acylhydrazones could be related to chelation of the divalent metal cofactor(s) in the influenza PA-Nter active site, we investigated the coordination properties of one model ligand (i.e. 19, H2L) towards Mg2+.	RESULTS
143	154	active site	site	Since the inhibitory activity of the N-acylhydrazones could be related to chelation of the divalent metal cofactor(s) in the influenza PA-Nter active site, we investigated the coordination properties of one model ligand (i.e. 19, H2L) towards Mg2+.	RESULTS
226	228	19	chemical	Since the inhibitory activity of the N-acylhydrazones could be related to chelation of the divalent metal cofactor(s) in the influenza PA-Nter active site, we investigated the coordination properties of one model ligand (i.e. 19, H2L) towards Mg2+.	RESULTS
230	233	H2L	chemical	Since the inhibitory activity of the N-acylhydrazones could be related to chelation of the divalent metal cofactor(s) in the influenza PA-Nter active site, we investigated the coordination properties of one model ligand (i.e. 19, H2L) towards Mg2+.	RESULTS
243	247	Mg2+	chemical	Since the inhibitory activity of the N-acylhydrazones could be related to chelation of the divalent metal cofactor(s) in the influenza PA-Nter active site, we investigated the coordination properties of one model ligand (i.e. 19, H2L) towards Mg2+.	RESULTS
99	112	triethylamine	chemical	Different reaction conditions were used (1:1 and 1:2 metal to ligand ratio, up to 4 equivalents of triethylamine), but in any case the same chemical species Mg(HL)2∙4H2O was recovered and conveniently characterized.	RESULTS
157	169	Mg(HL)2∙4H2O	chemical	Different reaction conditions were used (1:1 and 1:2 metal to ligand ratio, up to 4 equivalents of triethylamine), but in any case the same chemical species Mg(HL)2∙4H2O was recovered and conveniently characterized.	RESULTS
37	44	d6-DMSO	chemical	The use of a coordinating solvent as d6-DMSO causes partial decoordination of the ligand, but the 1H-NMR spectrum in MeOD, instead, shows only the signals attributable to the complex.	RESULTS
98	104	1H-NMR	experimental_method	The use of a coordinating solvent as d6-DMSO causes partial decoordination of the ligand, but the 1H-NMR spectrum in MeOD, instead, shows only the signals attributable to the complex.	RESULTS
105	113	spectrum	evidence	The use of a coordinating solvent as d6-DMSO causes partial decoordination of the ligand, but the 1H-NMR spectrum in MeOD, instead, shows only the signals attributable to the complex.	RESULTS
7	14	13C-NMR	experimental_method	In the 13C-NMR spectrum, the signal of the C = O quaternary carbon is practically unaffected by complexation, suggesting that the C = O group is weakly involved in the coordination to the metal ion.	RESULTS
15	23	spectrum	evidence	In the 13C-NMR spectrum, the signal of the C = O quaternary carbon is practically unaffected by complexation, suggesting that the C = O group is weakly involved in the coordination to the metal ion.	RESULTS
26	28	IR	experimental_method	This is confirmed, in the IR spectrum, by the shift of about 20 cm−1 of the C = O absorption, while a shift of 30–50 cm−1 is expected when the carbonylic oxygen is tightly bound to the metal ion.	RESULTS
29	37	spectrum	evidence	This is confirmed, in the IR spectrum, by the shift of about 20 cm−1 of the C = O absorption, while a shift of 30–50 cm−1 is expected when the carbonylic oxygen is tightly bound to the metal ion.	RESULTS
0	8	ESI-mass	experimental_method	ESI-mass spectra and elemental analysis confirmed the formula Mg(HL)2∙4H2O.	RESULTS
9	16	spectra	evidence	ESI-mass spectra and elemental analysis confirmed the formula Mg(HL)2∙4H2O.	RESULTS
21	39	elemental analysis	experimental_method	ESI-mass spectra and elemental analysis confirmed the formula Mg(HL)2∙4H2O.	RESULTS
62	74	Mg(HL)2∙4H2O	chemical	ESI-mass spectra and elemental analysis confirmed the formula Mg(HL)2∙4H2O.	RESULTS
28	43	N-acylhydrazone	chemical	The interaction between the N-acylhydrazone ligands and the magnesium cation was investigated also by means of UV-visible spectroscopy (UV-visible titrations of 23 and 19 with increasing amount of Mg(CH3COO)2 are shown in Figure S1).	RESULTS
60	69	magnesium	chemical	The interaction between the N-acylhydrazone ligands and the magnesium cation was investigated also by means of UV-visible spectroscopy (UV-visible titrations of 23 and 19 with increasing amount of Mg(CH3COO)2 are shown in Figure S1).	RESULTS
111	134	UV-visible spectroscopy	experimental_method	The interaction between the N-acylhydrazone ligands and the magnesium cation was investigated also by means of UV-visible spectroscopy (UV-visible titrations of 23 and 19 with increasing amount of Mg(CH3COO)2 are shown in Figure S1).	RESULTS
136	157	UV-visible titrations	experimental_method	The interaction between the N-acylhydrazone ligands and the magnesium cation was investigated also by means of UV-visible spectroscopy (UV-visible titrations of 23 and 19 with increasing amount of Mg(CH3COO)2 are shown in Figure S1).	RESULTS
161	163	23	chemical	The interaction between the N-acylhydrazone ligands and the magnesium cation was investigated also by means of UV-visible spectroscopy (UV-visible titrations of 23 and 19 with increasing amount of Mg(CH3COO)2 are shown in Figure S1).	RESULTS
168	170	19	chemical	The interaction between the N-acylhydrazone ligands and the magnesium cation was investigated also by means of UV-visible spectroscopy (UV-visible titrations of 23 and 19 with increasing amount of Mg(CH3COO)2 are shown in Figure S1).	RESULTS
176	193	increasing amount	experimental_method	The interaction between the N-acylhydrazone ligands and the magnesium cation was investigated also by means of UV-visible spectroscopy (UV-visible titrations of 23 and 19 with increasing amount of Mg(CH3COO)2 are shown in Figure S1).	RESULTS
197	208	Mg(CH3COO)2	chemical	The interaction between the N-acylhydrazone ligands and the magnesium cation was investigated also by means of UV-visible spectroscopy (UV-visible titrations of 23 and 19 with increasing amount of Mg(CH3COO)2 are shown in Figure S1).	RESULTS
4	12	spectrum	evidence	The spectrum of 19 includes a band at 313 nm assignable to n-π* transitions of the C = N and C = O groups.	RESULTS
16	18	19	chemical	The spectrum of 19 includes a band at 313 nm assignable to n-π* transitions of the C = N and C = O groups.	RESULTS
36	47	Mg(CH3COO)2	chemical	By adding increasing equivalents of Mg(CH3COO)2, the absorption around 400 nm increases, and a new band appears with a maximum at 397 nm.	RESULTS
44	46	23	chemical	When the same experiment was performed with 23, a different behavior was observed.	RESULTS
28	33	Mg2+,	chemical	Increasing concentration of Mg2+, in fact, caused a diminution in the maximum absorption, an isosbestic point is visible at about 345 nm, but a new band at 400 nm does not appear.	RESULTS
8	10	19	chemical	Ligands 19 and 23 coordinate the Mg2+ ions in different ways: 19 chelates the metal ion by using the deprotonated salicyl oxygen and the iminic nitrogen, while for 23, the gallic moiety is supposed to be involved (Fig. 4A,B versus C), leading to different, less extensive, modifications of the UV spectrum.	RESULTS
15	17	23	chemical	Ligands 19 and 23 coordinate the Mg2+ ions in different ways: 19 chelates the metal ion by using the deprotonated salicyl oxygen and the iminic nitrogen, while for 23, the gallic moiety is supposed to be involved (Fig. 4A,B versus C), leading to different, less extensive, modifications of the UV spectrum.	RESULTS
18	28	coordinate	bond_interaction	Ligands 19 and 23 coordinate the Mg2+ ions in different ways: 19 chelates the metal ion by using the deprotonated salicyl oxygen and the iminic nitrogen, while for 23, the gallic moiety is supposed to be involved (Fig. 4A,B versus C), leading to different, less extensive, modifications of the UV spectrum.	RESULTS
33	37	Mg2+	chemical	Ligands 19 and 23 coordinate the Mg2+ ions in different ways: 19 chelates the metal ion by using the deprotonated salicyl oxygen and the iminic nitrogen, while for 23, the gallic moiety is supposed to be involved (Fig. 4A,B versus C), leading to different, less extensive, modifications of the UV spectrum.	RESULTS
62	64	19	chemical	Ligands 19 and 23 coordinate the Mg2+ ions in different ways: 19 chelates the metal ion by using the deprotonated salicyl oxygen and the iminic nitrogen, while for 23, the gallic moiety is supposed to be involved (Fig. 4A,B versus C), leading to different, less extensive, modifications of the UV spectrum.	RESULTS
164	166	23	chemical	Ligands 19 and 23 coordinate the Mg2+ ions in different ways: 19 chelates the metal ion by using the deprotonated salicyl oxygen and the iminic nitrogen, while for 23, the gallic moiety is supposed to be involved (Fig. 4A,B versus C), leading to different, less extensive, modifications of the UV spectrum.	RESULTS
294	296	UV	experimental_method	Ligands 19 and 23 coordinate the Mg2+ ions in different ways: 19 chelates the metal ion by using the deprotonated salicyl oxygen and the iminic nitrogen, while for 23, the gallic moiety is supposed to be involved (Fig. 4A,B versus C), leading to different, less extensive, modifications of the UV spectrum.	RESULTS
297	305	spectrum	evidence	Ligands 19 and 23 coordinate the Mg2+ ions in different ways: 19 chelates the metal ion by using the deprotonated salicyl oxygen and the iminic nitrogen, while for 23, the gallic moiety is supposed to be involved (Fig. 4A,B versus C), leading to different, less extensive, modifications of the UV spectrum.	RESULTS
18	20	PA	protein	Inhibition of the PA-Nter enzyme	RESULTS
21	25	Nter	structure_element	Inhibition of the PA-Nter enzyme	RESULTS
63	72	influenza	taxonomy_domain	All the compounds were tested for their ability to inhibit the influenza endonuclease in an enzymatic plasmid-based assay with recombinant PA-Nter, as well as in cell-based influenza methods (i.e. virus yield and vRNP reconstitution assays).	RESULTS
73	85	endonuclease	protein_type	All the compounds were tested for their ability to inhibit the influenza endonuclease in an enzymatic plasmid-based assay with recombinant PA-Nter, as well as in cell-based influenza methods (i.e. virus yield and vRNP reconstitution assays).	RESULTS
92	121	enzymatic plasmid-based assay	experimental_method	All the compounds were tested for their ability to inhibit the influenza endonuclease in an enzymatic plasmid-based assay with recombinant PA-Nter, as well as in cell-based influenza methods (i.e. virus yield and vRNP reconstitution assays).	RESULTS
139	141	PA	protein	All the compounds were tested for their ability to inhibit the influenza endonuclease in an enzymatic plasmid-based assay with recombinant PA-Nter, as well as in cell-based influenza methods (i.e. virus yield and vRNP reconstitution assays).	RESULTS
142	146	Nter	structure_element	All the compounds were tested for their ability to inhibit the influenza endonuclease in an enzymatic plasmid-based assay with recombinant PA-Nter, as well as in cell-based influenza methods (i.e. virus yield and vRNP reconstitution assays).	RESULTS
162	190	cell-based influenza methods	experimental_method	All the compounds were tested for their ability to inhibit the influenza endonuclease in an enzymatic plasmid-based assay with recombinant PA-Nter, as well as in cell-based influenza methods (i.e. virus yield and vRNP reconstitution assays).	RESULTS
197	239	virus yield and vRNP reconstitution assays	experimental_method	All the compounds were tested for their ability to inhibit the influenza endonuclease in an enzymatic plasmid-based assay with recombinant PA-Nter, as well as in cell-based influenza methods (i.e. virus yield and vRNP reconstitution assays).	RESULTS
129	149	dose-response curves	evidence	The results are shown in Table 1 and summarized in Fig. 3 to visualize the structure-activity relationships; Figure S2 shows the dose-response curves for three representative compounds (i.e. 10, 13 and 23) in either the PA-enzyme or vRNP reconstitution assay.	RESULTS
191	193	10	chemical	The results are shown in Table 1 and summarized in Fig. 3 to visualize the structure-activity relationships; Figure S2 shows the dose-response curves for three representative compounds (i.e. 10, 13 and 23) in either the PA-enzyme or vRNP reconstitution assay.	RESULTS
195	197	13	chemical	The results are shown in Table 1 and summarized in Fig. 3 to visualize the structure-activity relationships; Figure S2 shows the dose-response curves for three representative compounds (i.e. 10, 13 and 23) in either the PA-enzyme or vRNP reconstitution assay.	RESULTS
202	204	23	chemical	The results are shown in Table 1 and summarized in Fig. 3 to visualize the structure-activity relationships; Figure S2 shows the dose-response curves for three representative compounds (i.e. 10, 13 and 23) in either the PA-enzyme or vRNP reconstitution assay.	RESULTS
220	258	PA-enzyme or vRNP reconstitution assay	experimental_method	The results are shown in Table 1 and summarized in Fig. 3 to visualize the structure-activity relationships; Figure S2 shows the dose-response curves for three representative compounds (i.e. 10, 13 and 23) in either the PA-enzyme or vRNP reconstitution assay.	RESULTS
23	27	IC50	evidence	The moderate activity (IC50 = 24 μM) of N’-2,3-dihydroxybenzylidene semicarbazide (1) was completely lost when the NH2 moiety was replaced by a hydrophobic heptyl chain (3), but it is less affected when a phenyl or a 2-hydroxyphenyl is present (5 and 7, IC50 = 84 and 54 μM, respectively).	RESULTS
40	81	N’-2,3-dihydroxybenzylidene semicarbazide	chemical	The moderate activity (IC50 = 24 μM) of N’-2,3-dihydroxybenzylidene semicarbazide (1) was completely lost when the NH2 moiety was replaced by a hydrophobic heptyl chain (3), but it is less affected when a phenyl or a 2-hydroxyphenyl is present (5 and 7, IC50 = 84 and 54 μM, respectively).	RESULTS
83	84	1	chemical	The moderate activity (IC50 = 24 μM) of N’-2,3-dihydroxybenzylidene semicarbazide (1) was completely lost when the NH2 moiety was replaced by a hydrophobic heptyl chain (3), but it is less affected when a phenyl or a 2-hydroxyphenyl is present (5 and 7, IC50 = 84 and 54 μM, respectively).	RESULTS
170	171	3	chemical	The moderate activity (IC50 = 24 μM) of N’-2,3-dihydroxybenzylidene semicarbazide (1) was completely lost when the NH2 moiety was replaced by a hydrophobic heptyl chain (3), but it is less affected when a phenyl or a 2-hydroxyphenyl is present (5 and 7, IC50 = 84 and 54 μM, respectively).	RESULTS
245	246	5	chemical	The moderate activity (IC50 = 24 μM) of N’-2,3-dihydroxybenzylidene semicarbazide (1) was completely lost when the NH2 moiety was replaced by a hydrophobic heptyl chain (3), but it is less affected when a phenyl or a 2-hydroxyphenyl is present (5 and 7, IC50 = 84 and 54 μM, respectively).	RESULTS
251	252	7	chemical	The moderate activity (IC50 = 24 μM) of N’-2,3-dihydroxybenzylidene semicarbazide (1) was completely lost when the NH2 moiety was replaced by a hydrophobic heptyl chain (3), but it is less affected when a phenyl or a 2-hydroxyphenyl is present (5 and 7, IC50 = 84 and 54 μM, respectively).	RESULTS
254	258	IC50	evidence	The moderate activity (IC50 = 24 μM) of N’-2,3-dihydroxybenzylidene semicarbazide (1) was completely lost when the NH2 moiety was replaced by a hydrophobic heptyl chain (3), but it is less affected when a phenyl or a 2-hydroxyphenyl is present (5 and 7, IC50 = 84 and 54 μM, respectively).	RESULTS
39	63	2,3-dihydroxybenzylidene	chemical	When the hydroxyl in position 3 on R1 (2,3-dihydroxybenzylidene) was replaced by a methoxy group (2-hydroxy-3-methoxybenzylidene), the activity disappeared (compounds 2, 4, 6 and 8).	RESULTS
98	128	2-hydroxy-3-methoxybenzylidene	chemical	When the hydroxyl in position 3 on R1 (2,3-dihydroxybenzylidene) was replaced by a methoxy group (2-hydroxy-3-methoxybenzylidene), the activity disappeared (compounds 2, 4, 6 and 8).	RESULTS
167	168	2	chemical	When the hydroxyl in position 3 on R1 (2,3-dihydroxybenzylidene) was replaced by a methoxy group (2-hydroxy-3-methoxybenzylidene), the activity disappeared (compounds 2, 4, 6 and 8).	RESULTS
170	171	4	chemical	When the hydroxyl in position 3 on R1 (2,3-dihydroxybenzylidene) was replaced by a methoxy group (2-hydroxy-3-methoxybenzylidene), the activity disappeared (compounds 2, 4, 6 and 8).	RESULTS
173	174	6	chemical	When the hydroxyl in position 3 on R1 (2,3-dihydroxybenzylidene) was replaced by a methoxy group (2-hydroxy-3-methoxybenzylidene), the activity disappeared (compounds 2, 4, 6 and 8).	RESULTS
179	180	8	chemical	When the hydroxyl in position 3 on R1 (2,3-dihydroxybenzylidene) was replaced by a methoxy group (2-hydroxy-3-methoxybenzylidene), the activity disappeared (compounds 2, 4, 6 and 8).	RESULTS
28	32	IC50	evidence	The activity is unaffected (IC50 values ranging from 45 to 75 μM) when going from two hydroxyls in R1 (7) to compounds with three hydroxyls (i.e. 9, 10 and 11).	RESULTS
103	104	7	chemical	The activity is unaffected (IC50 values ranging from 45 to 75 μM) when going from two hydroxyls in R1 (7) to compounds with three hydroxyls (i.e. 9, 10 and 11).	RESULTS
146	147	9	chemical	The activity is unaffected (IC50 values ranging from 45 to 75 μM) when going from two hydroxyls in R1 (7) to compounds with three hydroxyls (i.e. 9, 10 and 11).	RESULTS
149	151	10	chemical	The activity is unaffected (IC50 values ranging from 45 to 75 μM) when going from two hydroxyls in R1 (7) to compounds with three hydroxyls (i.e. 9, 10 and 11).	RESULTS
156	158	11	chemical	The activity is unaffected (IC50 values ranging from 45 to 75 μM) when going from two hydroxyls in R1 (7) to compounds with three hydroxyls (i.e. 9, 10 and 11).	RESULTS
11	13	11	chemical	Similarly, 11 (R1 = 3,4,5-trihydroxyphenyl, R2 = 2-hydroxyphenyl) had comparable activity as 27 (R1 = 3,4,5-trihydroxyphenyl, R2 = NH2).	RESULTS
93	95	27	chemical	Similarly, 11 (R1 = 3,4,5-trihydroxyphenyl, R2 = 2-hydroxyphenyl) had comparable activity as 27 (R1 = 3,4,5-trihydroxyphenyl, R2 = NH2).	RESULTS
71	73	11	chemical	Within the series carrying a 2-hydroxyphenyl R2 group, the activity of 11 is particularly intriguing.	RESULTS
0	2	11	chemical	11 does not have the possibility to chelate in a tridentate ONO fashion (mode A in Fig. 4), but it can coordinate two cations by means of its three OH groups in R1 (mode C, Fig. 4).	RESULTS
103	113	coordinate	bond_interaction	11 does not have the possibility to chelate in a tridentate ONO fashion (mode A in Fig. 4), but it can coordinate two cations by means of its three OH groups in R1 (mode C, Fig. 4).	RESULTS
53	70	crystal structure	evidence	Note that a similar chelating mode was observed in a crystal structure, solved by Cusack and coworkers, of PA-Nter endonuclease in complex with the inhibitor EGCG.	RESULTS
107	109	PA	protein	Note that a similar chelating mode was observed in a crystal structure, solved by Cusack and coworkers, of PA-Nter endonuclease in complex with the inhibitor EGCG.	RESULTS
110	114	Nter	structure_element	Note that a similar chelating mode was observed in a crystal structure, solved by Cusack and coworkers, of PA-Nter endonuclease in complex with the inhibitor EGCG.	RESULTS
115	127	endonuclease	protein_type	Note that a similar chelating mode was observed in a crystal structure, solved by Cusack and coworkers, of PA-Nter endonuclease in complex with the inhibitor EGCG.	RESULTS
128	143	in complex with	protein_state	Note that a similar chelating mode was observed in a crystal structure, solved by Cusack and coworkers, of PA-Nter endonuclease in complex with the inhibitor EGCG.	RESULTS
158	162	EGCG	chemical	Note that a similar chelating mode was observed in a crystal structure, solved by Cusack and coworkers, of PA-Nter endonuclease in complex with the inhibitor EGCG.	RESULTS
4	6	PA	protein	The PA-Nter inhibitory activity strongly depends on the number and position of hydroxyl substituents in R1 and R2: this is clearly highlighted by the data obtained with compounds 13–23, in which R2 is a 3,4,5-trihydroxyphenyl (gallic) group, the most active scaffold in our series.	RESULTS
7	11	Nter	structure_element	The PA-Nter inhibitory activity strongly depends on the number and position of hydroxyl substituents in R1 and R2: this is clearly highlighted by the data obtained with compounds 13–23, in which R2 is a 3,4,5-trihydroxyphenyl (gallic) group, the most active scaffold in our series.	RESULTS
179	184	13–23	chemical	The PA-Nter inhibitory activity strongly depends on the number and position of hydroxyl substituents in R1 and R2: this is clearly highlighted by the data obtained with compounds 13–23, in which R2 is a 3,4,5-trihydroxyphenyl (gallic) group, the most active scaffold in our series.	RESULTS
69	71	13	chemical	The analogue carrying an unsubstituted aromatic ring as R1 (compound 13) had moderate activity (IC50 = 69 μM).	RESULTS
96	100	IC50	evidence	The analogue carrying an unsubstituted aromatic ring as R1 (compound 13) had moderate activity (IC50 = 69 μM).	RESULTS
52	54	14	chemical	When one OH was added at position 2 of the R1 ring (14), the activity was lost.	RESULTS
83	85	15	chemical	Adding a second OH substituent at position 5 resulted in strong activity (compound 15, IC50 = 9 μM); medium activity for a 3-OH (18; IC50 = 83 μM), and marginal activity when the second OH is at position 4 (17, IC50 ≥ 370 μM).	RESULTS
87	91	IC50	evidence	Adding a second OH substituent at position 5 resulted in strong activity (compound 15, IC50 = 9 μM); medium activity for a 3-OH (18; IC50 = 83 μM), and marginal activity when the second OH is at position 4 (17, IC50 ≥ 370 μM).	RESULTS
129	131	18	chemical	Adding a second OH substituent at position 5 resulted in strong activity (compound 15, IC50 = 9 μM); medium activity for a 3-OH (18; IC50 = 83 μM), and marginal activity when the second OH is at position 4 (17, IC50 ≥ 370 μM).	RESULTS
133	137	IC50	evidence	Adding a second OH substituent at position 5 resulted in strong activity (compound 15, IC50 = 9 μM); medium activity for a 3-OH (18; IC50 = 83 μM), and marginal activity when the second OH is at position 4 (17, IC50 ≥ 370 μM).	RESULTS
207	209	17	chemical	Adding a second OH substituent at position 5 resulted in strong activity (compound 15, IC50 = 9 μM); medium activity for a 3-OH (18; IC50 = 83 μM), and marginal activity when the second OH is at position 4 (17, IC50 ≥ 370 μM).	RESULTS
211	215	IC50	evidence	Adding a second OH substituent at position 5 resulted in strong activity (compound 15, IC50 = 9 μM); medium activity for a 3-OH (18; IC50 = 83 μM), and marginal activity when the second OH is at position 4 (17, IC50 ≥ 370 μM).	RESULTS
35	37	19	chemical	The addition of a 3-methoxy group (19) abolished all inhibitory activity.	RESULTS
107	112	14–19	chemical	This cannot be related to variations in the chelating features displayed by the R1 moiety, since compounds 14–19 all have, in theory, the capacity to chelate one metal ion through the ortho-OH and iminic nitrogen (mode A in Fig. 4).	RESULTS
19	21	18	chemical	Moreover, compound 18 can, in principle, chelate the two M2+ ions in the active site according to mode B (Fig. 4), yet it (IC50 = 83 μM) has nine-fold lower activity than 15, that does not possess this two-metal chelating feature.	RESULTS
57	60	M2+	chemical	Moreover, compound 18 can, in principle, chelate the two M2+ ions in the active site according to mode B (Fig. 4), yet it (IC50 = 83 μM) has nine-fold lower activity than 15, that does not possess this two-metal chelating feature.	RESULTS
73	84	active site	site	Moreover, compound 18 can, in principle, chelate the two M2+ ions in the active site according to mode B (Fig. 4), yet it (IC50 = 83 μM) has nine-fold lower activity than 15, that does not possess this two-metal chelating feature.	RESULTS
123	127	IC50	evidence	Moreover, compound 18 can, in principle, chelate the two M2+ ions in the active site according to mode B (Fig. 4), yet it (IC50 = 83 μM) has nine-fold lower activity than 15, that does not possess this two-metal chelating feature.	RESULTS
171	173	15	chemical	Moreover, compound 18 can, in principle, chelate the two M2+ ions in the active site according to mode B (Fig. 4), yet it (IC50 = 83 μM) has nine-fold lower activity than 15, that does not possess this two-metal chelating feature.	RESULTS
184	195	active site	site	Therefore, we hypothesized that the inhibitory activity of the series containing the gallic moiety is determined by: (i) the capacity of the moiety R2 to chelate two metal ions in the active site of the enzyme, according to mode C (Fig. 4); and (ii) the presence and position of one or more hydroxyl substituents in R1, which may possibly result in ligand-protein interactions (e.g. through hydrogen bonds).	RESULTS
391	405	hydrogen bonds	bond_interaction	Therefore, we hypothesized that the inhibitory activity of the series containing the gallic moiety is determined by: (i) the capacity of the moiety R2 to chelate two metal ions in the active site of the enzyme, according to mode C (Fig. 4); and (ii) the presence and position of one or more hydroxyl substituents in R1, which may possibly result in ligand-protein interactions (e.g. through hydrogen bonds).	RESULTS
33	63	molecular docking calculations	experimental_method	This assumption was supported by molecular docking calculations and X-ray analysis of inhibitor 23 in complex with PA-Nter (vide infra).	RESULTS
68	82	X-ray analysis	experimental_method	This assumption was supported by molecular docking calculations and X-ray analysis of inhibitor 23 in complex with PA-Nter (vide infra).	RESULTS
96	98	23	chemical	This assumption was supported by molecular docking calculations and X-ray analysis of inhibitor 23 in complex with PA-Nter (vide infra).	RESULTS
99	114	in complex with	protein_state	This assumption was supported by molecular docking calculations and X-ray analysis of inhibitor 23 in complex with PA-Nter (vide infra).	RESULTS
115	117	PA	protein	This assumption was supported by molecular docking calculations and X-ray analysis of inhibitor 23 in complex with PA-Nter (vide infra).	RESULTS
118	122	Nter	structure_element	This assumption was supported by molecular docking calculations and X-ray analysis of inhibitor 23 in complex with PA-Nter (vide infra).	RESULTS
34	36	15	chemical	Substitution of the 5-hydroxyl in 15 by a methoxy group (16) causes a dramatic drop in activity (IC50 = 9 and 454 μM for 15 and 16, respectively).	RESULTS
57	59	16	chemical	Substitution of the 5-hydroxyl in 15 by a methoxy group (16) causes a dramatic drop in activity (IC50 = 9 and 454 μM for 15 and 16, respectively).	RESULTS
97	101	IC50	evidence	Substitution of the 5-hydroxyl in 15 by a methoxy group (16) causes a dramatic drop in activity (IC50 = 9 and 454 μM for 15 and 16, respectively).	RESULTS
121	123	15	chemical	Substitution of the 5-hydroxyl in 15 by a methoxy group (16) causes a dramatic drop in activity (IC50 = 9 and 454 μM for 15 and 16, respectively).	RESULTS
128	130	16	chemical	Substitution of the 5-hydroxyl in 15 by a methoxy group (16) causes a dramatic drop in activity (IC50 = 9 and 454 μM for 15 and 16, respectively).	RESULTS
81	83	20	chemical	In particular, all the compounds with a trihydroxylated phenyl group as R1 (i.e. 20, 21, 22 and 23) were able to inhibit PA-Nter quite potently.	RESULTS
85	87	21	chemical	In particular, all the compounds with a trihydroxylated phenyl group as R1 (i.e. 20, 21, 22 and 23) were able to inhibit PA-Nter quite potently.	RESULTS
89	91	22	chemical	In particular, all the compounds with a trihydroxylated phenyl group as R1 (i.e. 20, 21, 22 and 23) were able to inhibit PA-Nter quite potently.	RESULTS
96	98	23	chemical	In particular, all the compounds with a trihydroxylated phenyl group as R1 (i.e. 20, 21, 22 and 23) were able to inhibit PA-Nter quite potently.	RESULTS
121	123	PA	protein	In particular, all the compounds with a trihydroxylated phenyl group as R1 (i.e. 20, 21, 22 and 23) were able to inhibit PA-Nter quite potently.	RESULTS
124	128	Nter	structure_element	In particular, all the compounds with a trihydroxylated phenyl group as R1 (i.e. 20, 21, 22 and 23) were able to inhibit PA-Nter quite potently.	RESULTS
11	15	IC50	evidence	The lowest IC50 values were obtained for 21 and 23 (IC50 = 13 and 7 μM, respectively), which both have one of their three hydroxyl groups at position 5.	RESULTS
41	43	21	chemical	The lowest IC50 values were obtained for 21 and 23 (IC50 = 13 and 7 μM, respectively), which both have one of their three hydroxyl groups at position 5.	RESULTS
48	50	23	chemical	The lowest IC50 values were obtained for 21 and 23 (IC50 = 13 and 7 μM, respectively), which both have one of their three hydroxyl groups at position 5.	RESULTS
52	56	IC50	evidence	The lowest IC50 values were obtained for 21 and 23 (IC50 = 13 and 7 μM, respectively), which both have one of their three hydroxyl groups at position 5.	RESULTS
44	46	23	chemical	The most active compound in this series was 23, which lacks the hydroxyl group at position 2 of R1, further confirming that this function is undesirable or even detrimental for inhibitory activity against PA-Nter, as already noticed above for 14.	RESULTS
205	207	PA	protein	The most active compound in this series was 23, which lacks the hydroxyl group at position 2 of R1, further confirming that this function is undesirable or even detrimental for inhibitory activity against PA-Nter, as already noticed above for 14.	RESULTS
208	212	Nter	structure_element	The most active compound in this series was 23, which lacks the hydroxyl group at position 2 of R1, further confirming that this function is undesirable or even detrimental for inhibitory activity against PA-Nter, as already noticed above for 14.	RESULTS
243	245	14	chemical	The most active compound in this series was 23, which lacks the hydroxyl group at position 2 of R1, further confirming that this function is undesirable or even detrimental for inhibitory activity against PA-Nter, as already noticed above for 14.	RESULTS
64	73	chelation	bond_interaction	Consistent with a crucial role of the R2 gallic moiety in metal chelation, the strong activity of 15 was completely lost in its 3,4,5-trimethoxy analogue 12.	RESULTS
98	100	15	chemical	Consistent with a crucial role of the R2 gallic moiety in metal chelation, the strong activity of 15 was completely lost in its 3,4,5-trimethoxy analogue 12.	RESULTS
154	156	12	chemical	Consistent with a crucial role of the R2 gallic moiety in metal chelation, the strong activity of 15 was completely lost in its 3,4,5-trimethoxy analogue 12.	RESULTS
83	87	IC50	evidence	On the other hand, the R2 gallic containing compounds displayed moderate activity (IC50 values around 40 μM) when R1 was absent (i.e. the 3,4,5-trihydroxybenzohydrazide 28, Fig. 2), or composed of an extended ring system (26) or a pyrrole ring (25).	RESULTS
138	168	3,4,5-trihydroxybenzohydrazide	chemical	On the other hand, the R2 gallic containing compounds displayed moderate activity (IC50 values around 40 μM) when R1 was absent (i.e. the 3,4,5-trihydroxybenzohydrazide 28, Fig. 2), or composed of an extended ring system (26) or a pyrrole ring (25).	RESULTS
169	171	28	chemical	On the other hand, the R2 gallic containing compounds displayed moderate activity (IC50 values around 40 μM) when R1 was absent (i.e. the 3,4,5-trihydroxybenzohydrazide 28, Fig. 2), or composed of an extended ring system (26) or a pyrrole ring (25).	RESULTS
222	224	26	chemical	On the other hand, the R2 gallic containing compounds displayed moderate activity (IC50 values around 40 μM) when R1 was absent (i.e. the 3,4,5-trihydroxybenzohydrazide 28, Fig. 2), or composed of an extended ring system (26) or a pyrrole ring (25).	RESULTS
245	247	25	chemical	On the other hand, the R2 gallic containing compounds displayed moderate activity (IC50 values around 40 μM) when R1 was absent (i.e. the 3,4,5-trihydroxybenzohydrazide 28, Fig. 2), or composed of an extended ring system (26) or a pyrrole ring (25).	RESULTS
57	59	24	chemical	Still lower activity was seen with the pyridine analogue 24.	RESULTS
102	104	PA	protein	Evidently, the 3,4,5-trihydroxybenzyl moiety at R2 is fundamental but not sufficient to ensure potent PA-Nter endonuclease inhibition, since the interactions of R1 with the amino acid side chains of the protein appear crucial in modulating activity.	RESULTS
105	109	Nter	structure_element	Evidently, the 3,4,5-trihydroxybenzyl moiety at R2 is fundamental but not sufficient to ensure potent PA-Nter endonuclease inhibition, since the interactions of R1 with the amino acid side chains of the protein appear crucial in modulating activity.	RESULTS
110	122	endonuclease	protein_type	Evidently, the 3,4,5-trihydroxybenzyl moiety at R2 is fundamental but not sufficient to ensure potent PA-Nter endonuclease inhibition, since the interactions of R1 with the amino acid side chains of the protein appear crucial in modulating activity.	RESULTS
14	18	vRNP	complex_assembly	Inhibition of vRNP activity or virus replication in cells	RESULTS
31	36	virus	taxonomy_domain	Inhibition of vRNP activity or virus replication in cells	RESULTS
22	31	influenza	taxonomy_domain	To determine the anti-influenza virus activity of compounds 1–28 in cell culture, we performed an influenza vRNP reconstitution assay in human embryonic kidney 293 T (HEK293T) cells, then subjected the active compounds (i.e. EC50 < 100 μM) to a virus yield assay in influenza virus-infected Madin-Darby canine kidney (MDCK) cells (Table 1 and Fig. 3).	RESULTS
32	37	virus	taxonomy_domain	To determine the anti-influenza virus activity of compounds 1–28 in cell culture, we performed an influenza vRNP reconstitution assay in human embryonic kidney 293 T (HEK293T) cells, then subjected the active compounds (i.e. EC50 < 100 μM) to a virus yield assay in influenza virus-infected Madin-Darby canine kidney (MDCK) cells (Table 1 and Fig. 3).	RESULTS
60	64	1–28	chemical	To determine the anti-influenza virus activity of compounds 1–28 in cell culture, we performed an influenza vRNP reconstitution assay in human embryonic kidney 293 T (HEK293T) cells, then subjected the active compounds (i.e. EC50 < 100 μM) to a virus yield assay in influenza virus-infected Madin-Darby canine kidney (MDCK) cells (Table 1 and Fig. 3).	RESULTS
98	133	influenza vRNP reconstitution assay	experimental_method	To determine the anti-influenza virus activity of compounds 1–28 in cell culture, we performed an influenza vRNP reconstitution assay in human embryonic kidney 293 T (HEK293T) cells, then subjected the active compounds (i.e. EC50 < 100 μM) to a virus yield assay in influenza virus-infected Madin-Darby canine kidney (MDCK) cells (Table 1 and Fig. 3).	RESULTS
137	142	human	species	To determine the anti-influenza virus activity of compounds 1–28 in cell culture, we performed an influenza vRNP reconstitution assay in human embryonic kidney 293 T (HEK293T) cells, then subjected the active compounds (i.e. EC50 < 100 μM) to a virus yield assay in influenza virus-infected Madin-Darby canine kidney (MDCK) cells (Table 1 and Fig. 3).	RESULTS
225	229	EC50	evidence	To determine the anti-influenza virus activity of compounds 1–28 in cell culture, we performed an influenza vRNP reconstitution assay in human embryonic kidney 293 T (HEK293T) cells, then subjected the active compounds (i.e. EC50 < 100 μM) to a virus yield assay in influenza virus-infected Madin-Darby canine kidney (MDCK) cells (Table 1 and Fig. 3).	RESULTS
245	262	virus yield assay	experimental_method	To determine the anti-influenza virus activity of compounds 1–28 in cell culture, we performed an influenza vRNP reconstitution assay in human embryonic kidney 293 T (HEK293T) cells, then subjected the active compounds (i.e. EC50 < 100 μM) to a virus yield assay in influenza virus-infected Madin-Darby canine kidney (MDCK) cells (Table 1 and Fig. 3).	RESULTS
266	275	influenza	taxonomy_domain	To determine the anti-influenza virus activity of compounds 1–28 in cell culture, we performed an influenza vRNP reconstitution assay in human embryonic kidney 293 T (HEK293T) cells, then subjected the active compounds (i.e. EC50 < 100 μM) to a virus yield assay in influenza virus-infected Madin-Darby canine kidney (MDCK) cells (Table 1 and Fig. 3).	RESULTS
276	281	virus	taxonomy_domain	To determine the anti-influenza virus activity of compounds 1–28 in cell culture, we performed an influenza vRNP reconstitution assay in human embryonic kidney 293 T (HEK293T) cells, then subjected the active compounds (i.e. EC50 < 100 μM) to a virus yield assay in influenza virus-infected Madin-Darby canine kidney (MDCK) cells (Table 1 and Fig. 3).	RESULTS
9	24	N-acylhydrazone	chemical	For some N-acylhydrazone compounds, we observed quite potent and selective activity in the vRNP reconstitution assay.	RESULTS
91	116	vRNP reconstitution assay	experimental_method	For some N-acylhydrazone compounds, we observed quite potent and selective activity in the vRNP reconstitution assay.	RESULTS
45	50	viral	taxonomy_domain	This indicates that they are able to inhibit viral RNA synthesis and suggests that they could be classified as original PA inhibitors.	RESULTS
51	54	RNA	chemical	This indicates that they are able to inhibit viral RNA synthesis and suggests that they could be classified as original PA inhibitors.	RESULTS
120	122	PA	protein	This indicates that they are able to inhibit viral RNA synthesis and suggests that they could be classified as original PA inhibitors.	RESULTS
11	15	EC50	evidence	Values for EC50 (vRNP) or EC90 (virus yield) in the range of 0.4–18 μM were obtained for compounds 15 and 20–23, which all carry a 3,4,5-trihydroxyphenyl as R2, and possess either two (15) or three (20–23) hydroxyl substituents in the R1 moiety.	RESULTS
17	21	vRNP	complex_assembly	Values for EC50 (vRNP) or EC90 (virus yield) in the range of 0.4–18 μM were obtained for compounds 15 and 20–23, which all carry a 3,4,5-trihydroxyphenyl as R2, and possess either two (15) or three (20–23) hydroxyl substituents in the R1 moiety.	RESULTS
26	30	EC90	evidence	Values for EC50 (vRNP) or EC90 (virus yield) in the range of 0.4–18 μM were obtained for compounds 15 and 20–23, which all carry a 3,4,5-trihydroxyphenyl as R2, and possess either two (15) or three (20–23) hydroxyl substituents in the R1 moiety.	RESULTS
32	37	virus	taxonomy_domain	Values for EC50 (vRNP) or EC90 (virus yield) in the range of 0.4–18 μM were obtained for compounds 15 and 20–23, which all carry a 3,4,5-trihydroxyphenyl as R2, and possess either two (15) or three (20–23) hydroxyl substituents in the R1 moiety.	RESULTS
99	101	15	chemical	Values for EC50 (vRNP) or EC90 (virus yield) in the range of 0.4–18 μM were obtained for compounds 15 and 20–23, which all carry a 3,4,5-trihydroxyphenyl as R2, and possess either two (15) or three (20–23) hydroxyl substituents in the R1 moiety.	RESULTS
106	111	20–23	chemical	Values for EC50 (vRNP) or EC90 (virus yield) in the range of 0.4–18 μM were obtained for compounds 15 and 20–23, which all carry a 3,4,5-trihydroxyphenyl as R2, and possess either two (15) or three (20–23) hydroxyl substituents in the R1 moiety.	RESULTS
185	187	15	chemical	Values for EC50 (vRNP) or EC90 (virus yield) in the range of 0.4–18 μM were obtained for compounds 15 and 20–23, which all carry a 3,4,5-trihydroxyphenyl as R2, and possess either two (15) or three (20–23) hydroxyl substituents in the R1 moiety.	RESULTS
199	201	20	chemical	Values for EC50 (vRNP) or EC90 (virus yield) in the range of 0.4–18 μM were obtained for compounds 15 and 20–23, which all carry a 3,4,5-trihydroxyphenyl as R2, and possess either two (15) or three (20–23) hydroxyl substituents in the R1 moiety.	RESULTS
202	204	23	chemical	Values for EC50 (vRNP) or EC90 (virus yield) in the range of 0.4–18 μM were obtained for compounds 15 and 20–23, which all carry a 3,4,5-trihydroxyphenyl as R2, and possess either two (15) or three (20–23) hydroxyl substituents in the R1 moiety.	RESULTS
10	34	enzymatic PA-Nter assays	experimental_method	As in the enzymatic PA-Nter assays, the compounds having R2 as a gallic moiety (Fig. 3: 21, 22 and 23) showed slightly higher activity than the compounds carrying a 2-hydroxyl R2 group (9, 10 and 11); 10 and 22 have substantially the same EC50 in the vRNP reconstitution assay in HEK293T cells.	RESULTS
88	90	21	chemical	As in the enzymatic PA-Nter assays, the compounds having R2 as a gallic moiety (Fig. 3: 21, 22 and 23) showed slightly higher activity than the compounds carrying a 2-hydroxyl R2 group (9, 10 and 11); 10 and 22 have substantially the same EC50 in the vRNP reconstitution assay in HEK293T cells.	RESULTS
92	94	22	chemical	As in the enzymatic PA-Nter assays, the compounds having R2 as a gallic moiety (Fig. 3: 21, 22 and 23) showed slightly higher activity than the compounds carrying a 2-hydroxyl R2 group (9, 10 and 11); 10 and 22 have substantially the same EC50 in the vRNP reconstitution assay in HEK293T cells.	RESULTS
99	101	23	chemical	As in the enzymatic PA-Nter assays, the compounds having R2 as a gallic moiety (Fig. 3: 21, 22 and 23) showed slightly higher activity than the compounds carrying a 2-hydroxyl R2 group (9, 10 and 11); 10 and 22 have substantially the same EC50 in the vRNP reconstitution assay in HEK293T cells.	RESULTS
186	187	9	chemical	As in the enzymatic PA-Nter assays, the compounds having R2 as a gallic moiety (Fig. 3: 21, 22 and 23) showed slightly higher activity than the compounds carrying a 2-hydroxyl R2 group (9, 10 and 11); 10 and 22 have substantially the same EC50 in the vRNP reconstitution assay in HEK293T cells.	RESULTS
189	191	10	chemical	As in the enzymatic PA-Nter assays, the compounds having R2 as a gallic moiety (Fig. 3: 21, 22 and 23) showed slightly higher activity than the compounds carrying a 2-hydroxyl R2 group (9, 10 and 11); 10 and 22 have substantially the same EC50 in the vRNP reconstitution assay in HEK293T cells.	RESULTS
196	198	11	chemical	As in the enzymatic PA-Nter assays, the compounds having R2 as a gallic moiety (Fig. 3: 21, 22 and 23) showed slightly higher activity than the compounds carrying a 2-hydroxyl R2 group (9, 10 and 11); 10 and 22 have substantially the same EC50 in the vRNP reconstitution assay in HEK293T cells.	RESULTS
201	203	10	chemical	As in the enzymatic PA-Nter assays, the compounds having R2 as a gallic moiety (Fig. 3: 21, 22 and 23) showed slightly higher activity than the compounds carrying a 2-hydroxyl R2 group (9, 10 and 11); 10 and 22 have substantially the same EC50 in the vRNP reconstitution assay in HEK293T cells.	RESULTS
208	210	22	chemical	As in the enzymatic PA-Nter assays, the compounds having R2 as a gallic moiety (Fig. 3: 21, 22 and 23) showed slightly higher activity than the compounds carrying a 2-hydroxyl R2 group (9, 10 and 11); 10 and 22 have substantially the same EC50 in the vRNP reconstitution assay in HEK293T cells.	RESULTS
239	243	EC50	evidence	As in the enzymatic PA-Nter assays, the compounds having R2 as a gallic moiety (Fig. 3: 21, 22 and 23) showed slightly higher activity than the compounds carrying a 2-hydroxyl R2 group (9, 10 and 11); 10 and 22 have substantially the same EC50 in the vRNP reconstitution assay in HEK293T cells.	RESULTS
251	276	vRNP reconstitution assay	experimental_method	As in the enzymatic PA-Nter assays, the compounds having R2 as a gallic moiety (Fig. 3: 21, 22 and 23) showed slightly higher activity than the compounds carrying a 2-hydroxyl R2 group (9, 10 and 11); 10 and 22 have substantially the same EC50 in the vRNP reconstitution assay in HEK293T cells.	RESULTS
4	13	hydrazide	chemical	The hydrazide 28 displayed weak (virus yield) to moderate (vRNP reconstitution) activity, albeit less than the most active molecules in the 3,4,5-trihydroxyphenyl series (i.e. 18 and 21–23).	RESULTS
14	16	28	chemical	The hydrazide 28 displayed weak (virus yield) to moderate (vRNP reconstitution) activity, albeit less than the most active molecules in the 3,4,5-trihydroxyphenyl series (i.e. 18 and 21–23).	RESULTS
33	38	virus	taxonomy_domain	The hydrazide 28 displayed weak (virus yield) to moderate (vRNP reconstitution) activity, albeit less than the most active molecules in the 3,4,5-trihydroxyphenyl series (i.e. 18 and 21–23).	RESULTS
59	78	vRNP reconstitution	experimental_method	The hydrazide 28 displayed weak (virus yield) to moderate (vRNP reconstitution) activity, albeit less than the most active molecules in the 3,4,5-trihydroxyphenyl series (i.e. 18 and 21–23).	RESULTS
176	178	18	chemical	The hydrazide 28 displayed weak (virus yield) to moderate (vRNP reconstitution) activity, albeit less than the most active molecules in the 3,4,5-trihydroxyphenyl series (i.e. 18 and 21–23).	RESULTS
183	188	21–23	chemical	The hydrazide 28 displayed weak (virus yield) to moderate (vRNP reconstitution) activity, albeit less than the most active molecules in the 3,4,5-trihydroxyphenyl series (i.e. 18 and 21–23).	RESULTS
121	123	28	chemical	Even if there are no data indicating that the compounds reported in the paper are subject to hydrolysis, the activity of 28 could raise the concern that for some N-acylhydrazones the antiviral activity in cell culture may be related to their intracellular hydrolysis.	RESULTS
162	178	N-acylhydrazones	chemical	Even if there are no data indicating that the compounds reported in the paper are subject to hydrolysis, the activity of 28 could raise the concern that for some N-acylhydrazones the antiviral activity in cell culture may be related to their intracellular hydrolysis.	RESULTS
86	90	EC50	evidence	However, this is unlikely, since the antiviral potency showed large differences (i.e. EC50 values between 0.42 and 29 μM) for compounds with the same R2 but different R1 groups, meaning that R1 does play a role in modulating the antiviral effect.	RESULTS
32	56	2,3-dihydroxybenzylidene	chemical	Most compounds carrying as R1 a 2,3-dihydroxybenzylidene (i.e. 3, 5 and 7) or 2-hydroxy-3-methoxybenzylidene moiety (i.e. 4, 6 and 8) showed relatively high cytotoxicity in the vRNP assay, with CC50 values below 50 μM and a selectivity index (ratio of CC50 to EC50) below 8.	RESULTS
63	64	3	chemical	Most compounds carrying as R1 a 2,3-dihydroxybenzylidene (i.e. 3, 5 and 7) or 2-hydroxy-3-methoxybenzylidene moiety (i.e. 4, 6 and 8) showed relatively high cytotoxicity in the vRNP assay, with CC50 values below 50 μM and a selectivity index (ratio of CC50 to EC50) below 8.	RESULTS
66	67	5	chemical	Most compounds carrying as R1 a 2,3-dihydroxybenzylidene (i.e. 3, 5 and 7) or 2-hydroxy-3-methoxybenzylidene moiety (i.e. 4, 6 and 8) showed relatively high cytotoxicity in the vRNP assay, with CC50 values below 50 μM and a selectivity index (ratio of CC50 to EC50) below 8.	RESULTS
72	73	7	chemical	Most compounds carrying as R1 a 2,3-dihydroxybenzylidene (i.e. 3, 5 and 7) or 2-hydroxy-3-methoxybenzylidene moiety (i.e. 4, 6 and 8) showed relatively high cytotoxicity in the vRNP assay, with CC50 values below 50 μM and a selectivity index (ratio of CC50 to EC50) below 8.	RESULTS
78	108	2-hydroxy-3-methoxybenzylidene	chemical	Most compounds carrying as R1 a 2,3-dihydroxybenzylidene (i.e. 3, 5 and 7) or 2-hydroxy-3-methoxybenzylidene moiety (i.e. 4, 6 and 8) showed relatively high cytotoxicity in the vRNP assay, with CC50 values below 50 μM and a selectivity index (ratio of CC50 to EC50) below 8.	RESULTS
122	123	4	chemical	Most compounds carrying as R1 a 2,3-dihydroxybenzylidene (i.e. 3, 5 and 7) or 2-hydroxy-3-methoxybenzylidene moiety (i.e. 4, 6 and 8) showed relatively high cytotoxicity in the vRNP assay, with CC50 values below 50 μM and a selectivity index (ratio of CC50 to EC50) below 8.	RESULTS
125	126	6	chemical	Most compounds carrying as R1 a 2,3-dihydroxybenzylidene (i.e. 3, 5 and 7) or 2-hydroxy-3-methoxybenzylidene moiety (i.e. 4, 6 and 8) showed relatively high cytotoxicity in the vRNP assay, with CC50 values below 50 μM and a selectivity index (ratio of CC50 to EC50) below 8.	RESULTS
131	132	8	chemical	Most compounds carrying as R1 a 2,3-dihydroxybenzylidene (i.e. 3, 5 and 7) or 2-hydroxy-3-methoxybenzylidene moiety (i.e. 4, 6 and 8) showed relatively high cytotoxicity in the vRNP assay, with CC50 values below 50 μM and a selectivity index (ratio of CC50 to EC50) below 8.	RESULTS
177	187	vRNP assay	experimental_method	Most compounds carrying as R1 a 2,3-dihydroxybenzylidene (i.e. 3, 5 and 7) or 2-hydroxy-3-methoxybenzylidene moiety (i.e. 4, 6 and 8) showed relatively high cytotoxicity in the vRNP assay, with CC50 values below 50 μM and a selectivity index (ratio of CC50 to EC50) below 8.	RESULTS
194	198	CC50	evidence	Most compounds carrying as R1 a 2,3-dihydroxybenzylidene (i.e. 3, 5 and 7) or 2-hydroxy-3-methoxybenzylidene moiety (i.e. 4, 6 and 8) showed relatively high cytotoxicity in the vRNP assay, with CC50 values below 50 μM and a selectivity index (ratio of CC50 to EC50) below 8.	RESULTS
224	241	selectivity index	evidence	Most compounds carrying as R1 a 2,3-dihydroxybenzylidene (i.e. 3, 5 and 7) or 2-hydroxy-3-methoxybenzylidene moiety (i.e. 4, 6 and 8) showed relatively high cytotoxicity in the vRNP assay, with CC50 values below 50 μM and a selectivity index (ratio of CC50 to EC50) below 8.	RESULTS
252	256	CC50	evidence	Most compounds carrying as R1 a 2,3-dihydroxybenzylidene (i.e. 3, 5 and 7) or 2-hydroxy-3-methoxybenzylidene moiety (i.e. 4, 6 and 8) showed relatively high cytotoxicity in the vRNP assay, with CC50 values below 50 μM and a selectivity index (ratio of CC50 to EC50) below 8.	RESULTS
260	264	EC50	evidence	Most compounds carrying as R1 a 2,3-dihydroxybenzylidene (i.e. 3, 5 and 7) or 2-hydroxy-3-methoxybenzylidene moiety (i.e. 4, 6 and 8) showed relatively high cytotoxicity in the vRNP assay, with CC50 values below 50 μM and a selectivity index (ratio of CC50 to EC50) below 8.	RESULTS
27	29	18	chemical	Two notable exceptions are 18 and 19 (containing a 2,3-dihydroxybenzylidene or 2-hydroxy-3-methoxybenzylidene R1, respectively) which were not cytotoxic at 200 μM and displayed favorable antiviral selectivity.	RESULTS
34	36	19	chemical	Two notable exceptions are 18 and 19 (containing a 2,3-dihydroxybenzylidene or 2-hydroxy-3-methoxybenzylidene R1, respectively) which were not cytotoxic at 200 μM and displayed favorable antiviral selectivity.	RESULTS
51	75	2,3-dihydroxybenzylidene	chemical	Two notable exceptions are 18 and 19 (containing a 2,3-dihydroxybenzylidene or 2-hydroxy-3-methoxybenzylidene R1, respectively) which were not cytotoxic at 200 μM and displayed favorable antiviral selectivity.	RESULTS
79	109	2-hydroxy-3-methoxybenzylidene	chemical	Two notable exceptions are 18 and 19 (containing a 2,3-dihydroxybenzylidene or 2-hydroxy-3-methoxybenzylidene R1, respectively) which were not cytotoxic at 200 μM and displayed favorable antiviral selectivity.	RESULTS
5	20	N-acylhydrazone	chemical	Some N-acylhydrazone compounds were devoid of activity in the enzymatic assay, yet showed good to moderate efficacy in cell culture (e.g. 14 and 19, having EC50 values of 2.2 and 7.1 μM, respectively).	RESULTS
62	77	enzymatic assay	experimental_method	Some N-acylhydrazone compounds were devoid of activity in the enzymatic assay, yet showed good to moderate efficacy in cell culture (e.g. 14 and 19, having EC50 values of 2.2 and 7.1 μM, respectively).	RESULTS
138	140	14	chemical	Some N-acylhydrazone compounds were devoid of activity in the enzymatic assay, yet showed good to moderate efficacy in cell culture (e.g. 14 and 19, having EC50 values of 2.2 and 7.1 μM, respectively).	RESULTS
145	147	19	chemical	Some N-acylhydrazone compounds were devoid of activity in the enzymatic assay, yet showed good to moderate efficacy in cell culture (e.g. 14 and 19, having EC50 values of 2.2 and 7.1 μM, respectively).	RESULTS
156	160	EC50	evidence	Some N-acylhydrazone compounds were devoid of activity in the enzymatic assay, yet showed good to moderate efficacy in cell culture (e.g. 14 and 19, having EC50 values of 2.2 and 7.1 μM, respectively).	RESULTS
39	40	9	chemical	For most of the active compounds (i.e. 9, 11, 13, 15–21, 23, 24 and 26) a fair correlation was seen for the two cell-based assays, since the EC50 values obtained in the vRNP assay were maximum 5-fold different from the EC90 values in the virus yield assay.	RESULTS
42	44	11	chemical	For most of the active compounds (i.e. 9, 11, 13, 15–21, 23, 24 and 26) a fair correlation was seen for the two cell-based assays, since the EC50 values obtained in the vRNP assay were maximum 5-fold different from the EC90 values in the virus yield assay.	RESULTS
46	48	13	chemical	For most of the active compounds (i.e. 9, 11, 13, 15–21, 23, 24 and 26) a fair correlation was seen for the two cell-based assays, since the EC50 values obtained in the vRNP assay were maximum 5-fold different from the EC90 values in the virus yield assay.	RESULTS
50	55	15–21	chemical	For most of the active compounds (i.e. 9, 11, 13, 15–21, 23, 24 and 26) a fair correlation was seen for the two cell-based assays, since the EC50 values obtained in the vRNP assay were maximum 5-fold different from the EC90 values in the virus yield assay.	RESULTS
57	59	23	chemical	For most of the active compounds (i.e. 9, 11, 13, 15–21, 23, 24 and 26) a fair correlation was seen for the two cell-based assays, since the EC50 values obtained in the vRNP assay were maximum 5-fold different from the EC90 values in the virus yield assay.	RESULTS
61	63	24	chemical	For most of the active compounds (i.e. 9, 11, 13, 15–21, 23, 24 and 26) a fair correlation was seen for the two cell-based assays, since the EC50 values obtained in the vRNP assay were maximum 5-fold different from the EC90 values in the virus yield assay.	RESULTS
68	70	26	chemical	For most of the active compounds (i.e. 9, 11, 13, 15–21, 23, 24 and 26) a fair correlation was seen for the two cell-based assays, since the EC50 values obtained in the vRNP assay were maximum 5-fold different from the EC90 values in the virus yield assay.	RESULTS
112	129	cell-based assays	experimental_method	For most of the active compounds (i.e. 9, 11, 13, 15–21, 23, 24 and 26) a fair correlation was seen for the two cell-based assays, since the EC50 values obtained in the vRNP assay were maximum 5-fold different from the EC90 values in the virus yield assay.	RESULTS
141	145	EC50	evidence	For most of the active compounds (i.e. 9, 11, 13, 15–21, 23, 24 and 26) a fair correlation was seen for the two cell-based assays, since the EC50 values obtained in the vRNP assay were maximum 5-fold different from the EC90 values in the virus yield assay.	RESULTS
169	179	vRNP assay	experimental_method	For most of the active compounds (i.e. 9, 11, 13, 15–21, 23, 24 and 26) a fair correlation was seen for the two cell-based assays, since the EC50 values obtained in the vRNP assay were maximum 5-fold different from the EC90 values in the virus yield assay.	RESULTS
219	223	EC90	evidence	For most of the active compounds (i.e. 9, 11, 13, 15–21, 23, 24 and 26) a fair correlation was seen for the two cell-based assays, since the EC50 values obtained in the vRNP assay were maximum 5-fold different from the EC90 values in the virus yield assay.	RESULTS
238	255	virus yield assay	experimental_method	For most of the active compounds (i.e. 9, 11, 13, 15–21, 23, 24 and 26) a fair correlation was seen for the two cell-based assays, since the EC50 values obtained in the vRNP assay were maximum 5-fold different from the EC90 values in the virus yield assay.	RESULTS
58	59	7	chemical	On the other hand, this difference was 8-fold or more for 7, 10, 14, 22, 25 and 28.	RESULTS
61	63	10	chemical	On the other hand, this difference was 8-fold or more for 7, 10, 14, 22, 25 and 28.	RESULTS
65	67	14	chemical	On the other hand, this difference was 8-fold or more for 7, 10, 14, 22, 25 and 28.	RESULTS
69	71	22	chemical	On the other hand, this difference was 8-fold or more for 7, 10, 14, 22, 25 and 28.	RESULTS
73	75	25	chemical	On the other hand, this difference was 8-fold or more for 7, 10, 14, 22, 25 and 28.	RESULTS
80	82	28	chemical	On the other hand, this difference was 8-fold or more for 7, 10, 14, 22, 25 and 28.	RESULTS
5	20	N-acylhydrazone	chemical	Some N-acylhydrazone compounds showed good to moderate efficacy in the vRNP assay (e.g. 14 and 19, having EC50 values of 2.3 and 5.7 μM, respectively), yet were devoid of activity in the enzymatic assay.	RESULTS
71	81	vRNP assay	experimental_method	Some N-acylhydrazone compounds showed good to moderate efficacy in the vRNP assay (e.g. 14 and 19, having EC50 values of 2.3 and 5.7 μM, respectively), yet were devoid of activity in the enzymatic assay.	RESULTS
88	90	14	chemical	Some N-acylhydrazone compounds showed good to moderate efficacy in the vRNP assay (e.g. 14 and 19, having EC50 values of 2.3 and 5.7 μM, respectively), yet were devoid of activity in the enzymatic assay.	RESULTS
95	97	19	chemical	Some N-acylhydrazone compounds showed good to moderate efficacy in the vRNP assay (e.g. 14 and 19, having EC50 values of 2.3 and 5.7 μM, respectively), yet were devoid of activity in the enzymatic assay.	RESULTS
106	110	EC50	evidence	Some N-acylhydrazone compounds showed good to moderate efficacy in the vRNP assay (e.g. 14 and 19, having EC50 values of 2.3 and 5.7 μM, respectively), yet were devoid of activity in the enzymatic assay.	RESULTS
187	202	enzymatic assay	experimental_method	Some N-acylhydrazone compounds showed good to moderate efficacy in the vRNP assay (e.g. 14 and 19, having EC50 values of 2.3 and 5.7 μM, respectively), yet were devoid of activity in the enzymatic assay.	RESULTS
52	57	viral	taxonomy_domain	This observation suggests that they may inhibit the viral polymerase in an endonuclease-independent manner.	RESULTS
58	68	polymerase	protein_type	This observation suggests that they may inhibit the viral polymerase in an endonuclease-independent manner.	RESULTS
75	87	endonuclease	protein_type	This observation suggests that they may inhibit the viral polymerase in an endonuclease-independent manner.	RESULTS
61	77	N-acylhydrazones	chemical	To achieve a clear insight into the antiviral profile of the N-acylhydrazones, specific mechanistic experiments are currently ongoing in our laboratory, in which we are analyzing in full depth their effects on virus entry, polymerase-dependent RNA synthesis or the late stage (maturation and release) of the virus replication cycle.	RESULTS
210	215	virus	taxonomy_domain	To achieve a clear insight into the antiviral profile of the N-acylhydrazones, specific mechanistic experiments are currently ongoing in our laboratory, in which we are analyzing in full depth their effects on virus entry, polymerase-dependent RNA synthesis or the late stage (maturation and release) of the virus replication cycle.	RESULTS
223	233	polymerase	protein_type	To achieve a clear insight into the antiviral profile of the N-acylhydrazones, specific mechanistic experiments are currently ongoing in our laboratory, in which we are analyzing in full depth their effects on virus entry, polymerase-dependent RNA synthesis or the late stage (maturation and release) of the virus replication cycle.	RESULTS
244	247	RNA	chemical	To achieve a clear insight into the antiviral profile of the N-acylhydrazones, specific mechanistic experiments are currently ongoing in our laboratory, in which we are analyzing in full depth their effects on virus entry, polymerase-dependent RNA synthesis or the late stage (maturation and release) of the virus replication cycle.	RESULTS
308	313	virus	taxonomy_domain	To achieve a clear insight into the antiviral profile of the N-acylhydrazones, specific mechanistic experiments are currently ongoing in our laboratory, in which we are analyzing in full depth their effects on virus entry, polymerase-dependent RNA synthesis or the late stage (maturation and release) of the virus replication cycle.	RESULTS
0	15	Docking studies	experimental_method	Docking studies	RESULTS
76	95	docking simulations	experimental_method	In order to explore the possible binding mode of the synthesized compounds, docking simulations by GOLD program were performed by using the structural coordinates (PDB code 4AWM) for the PA-Nter endonuclease in complex with EGCG.	RESULTS
99	111	GOLD program	experimental_method	In order to explore the possible binding mode of the synthesized compounds, docking simulations by GOLD program were performed by using the structural coordinates (PDB code 4AWM) for the PA-Nter endonuclease in complex with EGCG.	RESULTS
187	189	PA	protein	In order to explore the possible binding mode of the synthesized compounds, docking simulations by GOLD program were performed by using the structural coordinates (PDB code 4AWM) for the PA-Nter endonuclease in complex with EGCG.	RESULTS
190	194	Nter	structure_element	In order to explore the possible binding mode of the synthesized compounds, docking simulations by GOLD program were performed by using the structural coordinates (PDB code 4AWM) for the PA-Nter endonuclease in complex with EGCG.	RESULTS
195	207	endonuclease	protein_type	In order to explore the possible binding mode of the synthesized compounds, docking simulations by GOLD program were performed by using the structural coordinates (PDB code 4AWM) for the PA-Nter endonuclease in complex with EGCG.	RESULTS
208	223	in complex with	protein_state	In order to explore the possible binding mode of the synthesized compounds, docking simulations by GOLD program were performed by using the structural coordinates (PDB code 4AWM) for the PA-Nter endonuclease in complex with EGCG.	RESULTS
224	228	EGCG	chemical	In order to explore the possible binding mode of the synthesized compounds, docking simulations by GOLD program were performed by using the structural coordinates (PDB code 4AWM) for the PA-Nter endonuclease in complex with EGCG.	RESULTS
128	140	superimposed	experimental_method	Considering that the position of the side-chains of some residues changes depending on which pocket the ligand is occupying, we superimposed some X-ray structures of complexes between PA-Nter endonuclease and known active ligands.	RESULTS
146	162	X-ray structures	evidence	Considering that the position of the side-chains of some residues changes depending on which pocket the ligand is occupying, we superimposed some X-ray structures of complexes between PA-Nter endonuclease and known active ligands.	RESULTS
184	186	PA	protein	Considering that the position of the side-chains of some residues changes depending on which pocket the ligand is occupying, we superimposed some X-ray structures of complexes between PA-Nter endonuclease and known active ligands.	RESULTS
187	191	Nter	structure_element	Considering that the position of the side-chains of some residues changes depending on which pocket the ligand is occupying, we superimposed some X-ray structures of complexes between PA-Nter endonuclease and known active ligands.	RESULTS
192	204	endonuclease	protein_type	Considering that the position of the side-chains of some residues changes depending on which pocket the ligand is occupying, we superimposed some X-ray structures of complexes between PA-Nter endonuclease and known active ligands.	RESULTS
50	55	Tyr24	residue_name_number	It was observed that the side-chain of amino acid Tyr24 shows greater movement than the other residues and for this reason we considered it as a flexible residue during the docking procedure.	RESULTS
145	153	flexible	protein_state	It was observed that the side-chain of amino acid Tyr24 shows greater movement than the other residues and for this reason we considered it as a flexible residue during the docking procedure.	RESULTS
173	190	docking procedure	experimental_method	It was observed that the side-chain of amino acid Tyr24 shows greater movement than the other residues and for this reason we considered it as a flexible residue during the docking procedure.	RESULTS
7	32	test docking calculations	experimental_method	First, test docking calculations, using EGCG, L-742,001 and 2-(4-(1H-tetrazol-5-yl)phenyl)-5-hydroxypyrimidin-4(3H)-one (Fig. 1), were carried out to compare experimental and predicted binding modes and validate docking procedure.	RESULTS
40	44	EGCG	chemical	First, test docking calculations, using EGCG, L-742,001 and 2-(4-(1H-tetrazol-5-yl)phenyl)-5-hydroxypyrimidin-4(3H)-one (Fig. 1), were carried out to compare experimental and predicted binding modes and validate docking procedure.	RESULTS
46	55	L-742,001	chemical	First, test docking calculations, using EGCG, L-742,001 and 2-(4-(1H-tetrazol-5-yl)phenyl)-5-hydroxypyrimidin-4(3H)-one (Fig. 1), were carried out to compare experimental and predicted binding modes and validate docking procedure.	RESULTS
60	119	2-(4-(1H-tetrazol-5-yl)phenyl)-5-hydroxypyrimidin-4(3H)-one	chemical	First, test docking calculations, using EGCG, L-742,001 and 2-(4-(1H-tetrazol-5-yl)phenyl)-5-hydroxypyrimidin-4(3H)-one (Fig. 1), were carried out to compare experimental and predicted binding modes and validate docking procedure.	RESULTS
212	229	docking procedure	experimental_method	First, test docking calculations, using EGCG, L-742,001 and 2-(4-(1H-tetrazol-5-yl)phenyl)-5-hydroxypyrimidin-4(3H)-one (Fig. 1), were carried out to compare experimental and predicted binding modes and validate docking procedure.	RESULTS
74	78	rmsd	evidence	Their best docking poses agreed well with the experimental binding modes (rmsd values of 0.8, 1.2 and 0.7, respectively).	RESULTS
6	13	docking	experimental_method	Next, docking of several N-acylhydrazones was performed and this generated a number of possible binding conformations, highlighting that the active site cavity of the PA endonuclease is quite spacious, as already demonstrated by crystallographic studies, and confirming the ability of this scaffold to chelate the two M2+ ions in different ways (Mode A-C in Fig. 4).	RESULTS
25	41	N-acylhydrazones	chemical	Next, docking of several N-acylhydrazones was performed and this generated a number of possible binding conformations, highlighting that the active site cavity of the PA endonuclease is quite spacious, as already demonstrated by crystallographic studies, and confirming the ability of this scaffold to chelate the two M2+ ions in different ways (Mode A-C in Fig. 4).	RESULTS
141	159	active site cavity	site	Next, docking of several N-acylhydrazones was performed and this generated a number of possible binding conformations, highlighting that the active site cavity of the PA endonuclease is quite spacious, as already demonstrated by crystallographic studies, and confirming the ability of this scaffold to chelate the two M2+ ions in different ways (Mode A-C in Fig. 4).	RESULTS
167	169	PA	protein	Next, docking of several N-acylhydrazones was performed and this generated a number of possible binding conformations, highlighting that the active site cavity of the PA endonuclease is quite spacious, as already demonstrated by crystallographic studies, and confirming the ability of this scaffold to chelate the two M2+ ions in different ways (Mode A-C in Fig. 4).	RESULTS
170	182	endonuclease	protein_type	Next, docking of several N-acylhydrazones was performed and this generated a number of possible binding conformations, highlighting that the active site cavity of the PA endonuclease is quite spacious, as already demonstrated by crystallographic studies, and confirming the ability of this scaffold to chelate the two M2+ ions in different ways (Mode A-C in Fig. 4).	RESULTS
229	253	crystallographic studies	experimental_method	Next, docking of several N-acylhydrazones was performed and this generated a number of possible binding conformations, highlighting that the active site cavity of the PA endonuclease is quite spacious, as already demonstrated by crystallographic studies, and confirming the ability of this scaffold to chelate the two M2+ ions in different ways (Mode A-C in Fig. 4).	RESULTS
318	321	M2+	chemical	Next, docking of several N-acylhydrazones was performed and this generated a number of possible binding conformations, highlighting that the active site cavity of the PA endonuclease is quite spacious, as already demonstrated by crystallographic studies, and confirming the ability of this scaffold to chelate the two M2+ ions in different ways (Mode A-C in Fig. 4).	RESULTS
59	78	GOLD cluster docked	experimental_method	Figure 5 displays the first (panel A) and second (panel B) GOLD cluster docked solutions for compound 23.	RESULTS
102	104	23	chemical	Figure 5 displays the first (panel A) and second (panel B) GOLD cluster docked solutions for compound 23.	RESULTS
18	28	structures	evidence	These two complex structures represent the largest clusters with similar fitness values (59.20 and 58.65, respectively).	RESULTS
15	17	23	chemical	In both cases, 23 appears able to coordinate the two M2+ ions in the active site through the three contiguous OH groups (Fig. 5).	RESULTS
34	44	coordinate	bond_interaction	In both cases, 23 appears able to coordinate the two M2+ ions in the active site through the three contiguous OH groups (Fig. 5).	RESULTS
53	56	M2+	chemical	In both cases, 23 appears able to coordinate the two M2+ ions in the active site through the three contiguous OH groups (Fig. 5).	RESULTS
69	80	active site	site	In both cases, 23 appears able to coordinate the two M2+ ions in the active site through the three contiguous OH groups (Fig. 5).	RESULTS
13	15	23	chemical	In addition, 23 was predicted to form two hydrogen bonding interactions, i.e. with the catalytic Lys134 on the one side and Glu26 on the other side.	RESULTS
42	71	hydrogen bonding interactions	bond_interaction	In addition, 23 was predicted to form two hydrogen bonding interactions, i.e. with the catalytic Lys134 on the one side and Glu26 on the other side.	RESULTS
87	96	catalytic	protein_state	In addition, 23 was predicted to form two hydrogen bonding interactions, i.e. with the catalytic Lys134 on the one side and Glu26 on the other side.	RESULTS
97	103	Lys134	residue_name_number	In addition, 23 was predicted to form two hydrogen bonding interactions, i.e. with the catalytic Lys134 on the one side and Glu26 on the other side.	RESULTS
124	129	Glu26	residue_name_number	In addition, 23 was predicted to form two hydrogen bonding interactions, i.e. with the catalytic Lys134 on the one side and Glu26 on the other side.	RESULTS
51	53	23	chemical	Furthermore, in these two different binding modes, 23 forms π–π interactions with the aromatic ring of Tyr24, in a fashion similar to that described for other endonuclease inhibitors, i.e. EGCG and L-742,001.	RESULTS
60	76	π–π interactions	bond_interaction	Furthermore, in these two different binding modes, 23 forms π–π interactions with the aromatic ring of Tyr24, in a fashion similar to that described for other endonuclease inhibitors, i.e. EGCG and L-742,001.	RESULTS
103	108	Tyr24	residue_name_number	Furthermore, in these two different binding modes, 23 forms π–π interactions with the aromatic ring of Tyr24, in a fashion similar to that described for other endonuclease inhibitors, i.e. EGCG and L-742,001.	RESULTS
159	171	endonuclease	protein_type	Furthermore, in these two different binding modes, 23 forms π–π interactions with the aromatic ring of Tyr24, in a fashion similar to that described for other endonuclease inhibitors, i.e. EGCG and L-742,001.	RESULTS
189	193	EGCG	chemical	Furthermore, in these two different binding modes, 23 forms π–π interactions with the aromatic ring of Tyr24, in a fashion similar to that described for other endonuclease inhibitors, i.e. EGCG and L-742,001.	RESULTS
198	207	L-742,001	chemical	Furthermore, in these two different binding modes, 23 forms π–π interactions with the aromatic ring of Tyr24, in a fashion similar to that described for other endonuclease inhibitors, i.e. EGCG and L-742,001.	RESULTS
42	44	15	chemical	The best docked conformation for compound 15 (Fig. 6, fitness value 68.56), which has an activity slightly lower than 23, reveals a different role for the gallic moiety.	RESULTS
54	67	fitness value	evidence	The best docked conformation for compound 15 (Fig. 6, fitness value 68.56), which has an activity slightly lower than 23, reveals a different role for the gallic moiety.	RESULTS
29	58	hydrogen bonding interactions	bond_interaction	The ligand seems to form two hydrogen bonding interactions with Tyr130 as well as a cation–π interaction with Lys134.	RESULTS
64	70	Tyr130	residue_name_number	The ligand seems to form two hydrogen bonding interactions with Tyr130 as well as a cation–π interaction with Lys134.	RESULTS
84	104	cation–π interaction	bond_interaction	The ligand seems to form two hydrogen bonding interactions with Tyr130 as well as a cation–π interaction with Lys134.	RESULTS
110	116	Lys134	residue_name_number	The ligand seems to form two hydrogen bonding interactions with Tyr130 as well as a cation–π interaction with Lys134.	RESULTS
0	6	Tyr130	residue_name_number	Tyr130 lies in a pocket that also contains Arg124, a residue that was proposed to have a crucial role in binding of the RNA substrate.	RESULTS
17	23	pocket	site	Tyr130 lies in a pocket that also contains Arg124, a residue that was proposed to have a crucial role in binding of the RNA substrate.	RESULTS
43	49	Arg124	residue_name_number	Tyr130 lies in a pocket that also contains Arg124, a residue that was proposed to have a crucial role in binding of the RNA substrate.	RESULTS
120	123	RNA	chemical	Tyr130 lies in a pocket that also contains Arg124, a residue that was proposed to have a crucial role in binding of the RNA substrate.	RESULTS
9	11	15	chemical	Compound 15 appears further stabilized by hydrogen bonding interactions between two hydroxyl groups and Arg82 and Asp108.	RESULTS
42	71	hydrogen bonding interactions	bond_interaction	Compound 15 appears further stabilized by hydrogen bonding interactions between two hydroxyl groups and Arg82 and Asp108.	RESULTS
104	109	Arg82	residue_name_number	Compound 15 appears further stabilized by hydrogen bonding interactions between two hydroxyl groups and Arg82 and Asp108.	RESULTS
114	120	Asp108	residue_name_number	Compound 15 appears further stabilized by hydrogen bonding interactions between two hydroxyl groups and Arg82 and Asp108.	RESULTS
14	23	chelation	bond_interaction	In this case, chelation of the two M2+ ions is carried out by involving the imine group (mode A in Fig. 4).	RESULTS
35	38	M2+	chemical	In this case, chelation of the two M2+ ions is carried out by involving the imine group (mode A in Fig. 4).	RESULTS
44	46	23	chemical	It is important to highlight that compounds 23 and 15, although in different ways, both are able to chelate the metal cofactors and to establish interactions with highly conserved aminoacids (Tyr24, Glu26, Arg124, Tyr130 and Lys134) that are very important for both endonuclease activity and transcription in vitro.	RESULTS
51	53	15	chemical	It is important to highlight that compounds 23 and 15, although in different ways, both are able to chelate the metal cofactors and to establish interactions with highly conserved aminoacids (Tyr24, Glu26, Arg124, Tyr130 and Lys134) that are very important for both endonuclease activity and transcription in vitro.	RESULTS
163	179	highly conserved	protein_state	It is important to highlight that compounds 23 and 15, although in different ways, both are able to chelate the metal cofactors and to establish interactions with highly conserved aminoacids (Tyr24, Glu26, Arg124, Tyr130 and Lys134) that are very important for both endonuclease activity and transcription in vitro.	RESULTS
192	197	Tyr24	residue_name_number	It is important to highlight that compounds 23 and 15, although in different ways, both are able to chelate the metal cofactors and to establish interactions with highly conserved aminoacids (Tyr24, Glu26, Arg124, Tyr130 and Lys134) that are very important for both endonuclease activity and transcription in vitro.	RESULTS
199	204	Glu26	residue_name_number	It is important to highlight that compounds 23 and 15, although in different ways, both are able to chelate the metal cofactors and to establish interactions with highly conserved aminoacids (Tyr24, Glu26, Arg124, Tyr130 and Lys134) that are very important for both endonuclease activity and transcription in vitro.	RESULTS
206	212	Arg124	residue_name_number	It is important to highlight that compounds 23 and 15, although in different ways, both are able to chelate the metal cofactors and to establish interactions with highly conserved aminoacids (Tyr24, Glu26, Arg124, Tyr130 and Lys134) that are very important for both endonuclease activity and transcription in vitro.	RESULTS
214	220	Tyr130	residue_name_number	It is important to highlight that compounds 23 and 15, although in different ways, both are able to chelate the metal cofactors and to establish interactions with highly conserved aminoacids (Tyr24, Glu26, Arg124, Tyr130 and Lys134) that are very important for both endonuclease activity and transcription in vitro.	RESULTS
225	231	Lys134	residue_name_number	It is important to highlight that compounds 23 and 15, although in different ways, both are able to chelate the metal cofactors and to establish interactions with highly conserved aminoacids (Tyr24, Glu26, Arg124, Tyr130 and Lys134) that are very important for both endonuclease activity and transcription in vitro.	RESULTS
266	278	endonuclease	protein_type	It is important to highlight that compounds 23 and 15, although in different ways, both are able to chelate the metal cofactors and to establish interactions with highly conserved aminoacids (Tyr24, Glu26, Arg124, Tyr130 and Lys134) that are very important for both endonuclease activity and transcription in vitro.	RESULTS
91	93	15	chemical	The crucial role of such interactions is underlined by the differences in activity between 15 (IC50 = 9.0 μM) and 19 (>500 μM): their coordinating features are similar, since both coordinate to the divalent metal ion through the phenolic oxygen, the iminic nitrogen and the carbonylic oxygen (mode A in Fig. 4), but the biological activity could be related to their different ability to engage interactions with the protein environment.	RESULTS
95	99	IC50	evidence	The crucial role of such interactions is underlined by the differences in activity between 15 (IC50 = 9.0 μM) and 19 (>500 μM): their coordinating features are similar, since both coordinate to the divalent metal ion through the phenolic oxygen, the iminic nitrogen and the carbonylic oxygen (mode A in Fig. 4), but the biological activity could be related to their different ability to engage interactions with the protein environment.	RESULTS
114	116	19	chemical	The crucial role of such interactions is underlined by the differences in activity between 15 (IC50 = 9.0 μM) and 19 (>500 μM): their coordinating features are similar, since both coordinate to the divalent metal ion through the phenolic oxygen, the iminic nitrogen and the carbonylic oxygen (mode A in Fig. 4), but the biological activity could be related to their different ability to engage interactions with the protein environment.	RESULTS
180	190	coordinate	bond_interaction	The crucial role of such interactions is underlined by the differences in activity between 15 (IC50 = 9.0 μM) and 19 (>500 μM): their coordinating features are similar, since both coordinate to the divalent metal ion through the phenolic oxygen, the iminic nitrogen and the carbonylic oxygen (mode A in Fig. 4), but the biological activity could be related to their different ability to engage interactions with the protein environment.	RESULTS
0	24	Crystallographic Studies	experimental_method	Crystallographic Studies	RESULTS
22	36	co-crystallize	experimental_method	Attempts were made to co-crystallize PA-Nter with 15, 20, 21 and 23 in one to four molar excess.	RESULTS
37	39	PA	protein	Attempts were made to co-crystallize PA-Nter with 15, 20, 21 and 23 in one to four molar excess.	RESULTS
40	44	Nter	structure_element	Attempts were made to co-crystallize PA-Nter with 15, 20, 21 and 23 in one to four molar excess.	RESULTS
50	52	15	chemical	Attempts were made to co-crystallize PA-Nter with 15, 20, 21 and 23 in one to four molar excess.	RESULTS
54	56	20	chemical	Attempts were made to co-crystallize PA-Nter with 15, 20, 21 and 23 in one to four molar excess.	RESULTS
58	60	21	chemical	Attempts were made to co-crystallize PA-Nter with 15, 20, 21 and 23 in one to four molar excess.	RESULTS
65	67	23	chemical	Attempts were made to co-crystallize PA-Nter with 15, 20, 21 and 23 in one to four molar excess.	RESULTS
6	14	crystals	evidence	While crystals appeared and diffracted well, upon data processing, no or very little electron density for the inhibitors was observed.	RESULTS
85	101	electron density	evidence	While crystals appeared and diffracted well, upon data processing, no or very little electron density for the inhibitors was observed.	RESULTS
17	20	apo	protein_state	Attempts to soak apo crystals in crystallization solution containing 5 mM inhibitor overnight also did not result in substantial electron density for the inhibitor.	RESULTS
21	29	crystals	evidence	Attempts to soak apo crystals in crystallization solution containing 5 mM inhibitor overnight also did not result in substantial electron density for the inhibitor.	RESULTS
129	145	electron density	evidence	Attempts to soak apo crystals in crystallization solution containing 5 mM inhibitor overnight also did not result in substantial electron density for the inhibitor.	RESULTS
101	104	apo	protein_state	As a last resort, dry powder of the inhibitor was sprinkled over the crystallization drop containing apo crystals and left over night.	RESULTS
105	113	crystals	evidence	As a last resort, dry powder of the inhibitor was sprinkled over the crystallization drop containing apo crystals and left over night.	RESULTS
44	46	23	chemical	This experiment was successful for compound 23, the crystals diffracted to 2.15 Å and diffraction data were collected (PDB ID 5EGA).	RESULTS
52	60	crystals	evidence	This experiment was successful for compound 23, the crystals diffracted to 2.15 Å and diffraction data were collected (PDB ID 5EGA).	RESULTS
12	21	structure	evidence	The refined structure shows unambiguous electron density for the inhibitor (Table S1 and Fig. 7).	RESULTS
40	56	electron density	evidence	The refined structure shows unambiguous electron density for the inhibitor (Table S1 and Fig. 7).	RESULTS
4	21	complex structure	evidence	The complex structure confirms one of the two binding modes predicted by the docking simulations (Fig. 5, panel B).	RESULTS
77	96	docking simulations	experimental_method	The complex structure confirms one of the two binding modes predicted by the docking simulations (Fig. 5, panel B).	RESULTS
32	41	manganese	chemical	The galloyl moiety chelates the manganese ions, while the trihydroxyphenyl group stacks against the Tyr24 side chain.	RESULTS
100	105	Tyr24	residue_name_number	The galloyl moiety chelates the manganese ions, while the trihydroxyphenyl group stacks against the Tyr24 side chain.	RESULTS
84	98	hydrogen bonds	bond_interaction	It is interesting to note that two of these hydroxyl groups are in position to form hydrogen bonds with the side chain of Glu26 and Lys34 (Fig. 7).	RESULTS
122	127	Glu26	residue_name_number	It is interesting to note that two of these hydroxyl groups are in position to form hydrogen bonds with the side chain of Glu26 and Lys34 (Fig. 7).	RESULTS
132	137	Lys34	residue_name_number	It is interesting to note that two of these hydroxyl groups are in position to form hydrogen bonds with the side chain of Glu26 and Lys34 (Fig. 7).	RESULTS
147	152	Glu26	residue_name_number	These interactions suggest that other functional groups, e.g. halogens, could be used in place of the hydroxyl groups for better interactions with Glu26 and Lys34 side chains, and the inhibitory potency of these compounds could be further improved.	RESULTS
157	162	Lys34	residue_name_number	These interactions suggest that other functional groups, e.g. halogens, could be used in place of the hydroxyl groups for better interactions with Glu26 and Lys34 side chains, and the inhibitory potency of these compounds could be further improved.	RESULTS
51	60	influenza	taxonomy_domain	The development of new agents for the treatment of influenza infection that exert their action by inhibition of the endonuclease activity of influenza RNA-dependent RNA polymerase is a strategy that recently is gaining a lot of interest.	CONCL
116	128	endonuclease	protein_type	The development of new agents for the treatment of influenza infection that exert their action by inhibition of the endonuclease activity of influenza RNA-dependent RNA polymerase is a strategy that recently is gaining a lot of interest.	CONCL
141	150	influenza	taxonomy_domain	The development of new agents for the treatment of influenza infection that exert their action by inhibition of the endonuclease activity of influenza RNA-dependent RNA polymerase is a strategy that recently is gaining a lot of interest.	CONCL
151	179	RNA-dependent RNA polymerase	protein_type	The development of new agents for the treatment of influenza infection that exert their action by inhibition of the endonuclease activity of influenza RNA-dependent RNA polymerase is a strategy that recently is gaining a lot of interest.	CONCL
35	50	N-acylhydrazone	chemical	The results here presented add the N-acylhydrazone scaffold to the library of the chelating molecules with potent antiviral activity (EC90 < 5 μM, virus yield assay in influenza virus-infected MDCK cells).	CONCL
134	138	EC90	evidence	The results here presented add the N-acylhydrazone scaffold to the library of the chelating molecules with potent antiviral activity (EC90 < 5 μM, virus yield assay in influenza virus-infected MDCK cells).	CONCL
147	164	virus yield assay	experimental_method	The results here presented add the N-acylhydrazone scaffold to the library of the chelating molecules with potent antiviral activity (EC90 < 5 μM, virus yield assay in influenza virus-infected MDCK cells).	CONCL
168	177	influenza	taxonomy_domain	The results here presented add the N-acylhydrazone scaffold to the library of the chelating molecules with potent antiviral activity (EC90 < 5 μM, virus yield assay in influenza virus-infected MDCK cells).	CONCL
178	183	virus	taxonomy_domain	The results here presented add the N-acylhydrazone scaffold to the library of the chelating molecules with potent antiviral activity (EC90 < 5 μM, virus yield assay in influenza virus-infected MDCK cells).	CONCL
4	13	structure	evidence	The structure of the N-acylhydrazone 23 co-crystallized with PA-Nter is important not only because confirms that the polyhydroxypheyl group efficiently coordinates two metal ions in the active site of the enzyme, but also because highlights the importance of the (flexible) inhibitor backbone in order to engage effective interactions with crucial aminoacids of the protein.	CONCL
21	36	N-acylhydrazone	chemical	The structure of the N-acylhydrazone 23 co-crystallized with PA-Nter is important not only because confirms that the polyhydroxypheyl group efficiently coordinates two metal ions in the active site of the enzyme, but also because highlights the importance of the (flexible) inhibitor backbone in order to engage effective interactions with crucial aminoacids of the protein.	CONCL
37	39	23	chemical	The structure of the N-acylhydrazone 23 co-crystallized with PA-Nter is important not only because confirms that the polyhydroxypheyl group efficiently coordinates two metal ions in the active site of the enzyme, but also because highlights the importance of the (flexible) inhibitor backbone in order to engage effective interactions with crucial aminoacids of the protein.	CONCL
40	55	co-crystallized	experimental_method	The structure of the N-acylhydrazone 23 co-crystallized with PA-Nter is important not only because confirms that the polyhydroxypheyl group efficiently coordinates two metal ions in the active site of the enzyme, but also because highlights the importance of the (flexible) inhibitor backbone in order to engage effective interactions with crucial aminoacids of the protein.	CONCL
61	63	PA	protein	The structure of the N-acylhydrazone 23 co-crystallized with PA-Nter is important not only because confirms that the polyhydroxypheyl group efficiently coordinates two metal ions in the active site of the enzyme, but also because highlights the importance of the (flexible) inhibitor backbone in order to engage effective interactions with crucial aminoacids of the protein.	CONCL
64	68	Nter	structure_element	The structure of the N-acylhydrazone 23 co-crystallized with PA-Nter is important not only because confirms that the polyhydroxypheyl group efficiently coordinates two metal ions in the active site of the enzyme, but also because highlights the importance of the (flexible) inhibitor backbone in order to engage effective interactions with crucial aminoacids of the protein.	CONCL
152	163	coordinates	bond_interaction	The structure of the N-acylhydrazone 23 co-crystallized with PA-Nter is important not only because confirms that the polyhydroxypheyl group efficiently coordinates two metal ions in the active site of the enzyme, but also because highlights the importance of the (flexible) inhibitor backbone in order to engage effective interactions with crucial aminoacids of the protein.	CONCL
168	173	metal	chemical	The structure of the N-acylhydrazone 23 co-crystallized with PA-Nter is important not only because confirms that the polyhydroxypheyl group efficiently coordinates two metal ions in the active site of the enzyme, but also because highlights the importance of the (flexible) inhibitor backbone in order to engage effective interactions with crucial aminoacids of the protein.	CONCL
186	197	active site	site	The structure of the N-acylhydrazone 23 co-crystallized with PA-Nter is important not only because confirms that the polyhydroxypheyl group efficiently coordinates two metal ions in the active site of the enzyme, but also because highlights the importance of the (flexible) inhibitor backbone in order to engage effective interactions with crucial aminoacids of the protein.	CONCL
18	30	endonuclease	protein_type	Inhibition of the endonuclease activity of influenza RNA-dependent RNA polymerase could represent another example, after carbonic anhydrase, histone deacetylase, and HIV-1 integrase, of metal binding as a successful strategy in drug design.	CONCL
43	52	influenza	taxonomy_domain	Inhibition of the endonuclease activity of influenza RNA-dependent RNA polymerase could represent another example, after carbonic anhydrase, histone deacetylase, and HIV-1 integrase, of metal binding as a successful strategy in drug design.	CONCL
53	81	RNA-dependent RNA polymerase	protein_type	Inhibition of the endonuclease activity of influenza RNA-dependent RNA polymerase could represent another example, after carbonic anhydrase, histone deacetylase, and HIV-1 integrase, of metal binding as a successful strategy in drug design.	CONCL
121	139	carbonic anhydrase	protein_type	Inhibition of the endonuclease activity of influenza RNA-dependent RNA polymerase could represent another example, after carbonic anhydrase, histone deacetylase, and HIV-1 integrase, of metal binding as a successful strategy in drug design.	CONCL
141	160	histone deacetylase	protein_type	Inhibition of the endonuclease activity of influenza RNA-dependent RNA polymerase could represent another example, after carbonic anhydrase, histone deacetylase, and HIV-1 integrase, of metal binding as a successful strategy in drug design.	CONCL
166	171	HIV-1	species	Inhibition of the endonuclease activity of influenza RNA-dependent RNA polymerase could represent another example, after carbonic anhydrase, histone deacetylase, and HIV-1 integrase, of metal binding as a successful strategy in drug design.	CONCL
172	181	integrase	protein_type	Inhibition of the endonuclease activity of influenza RNA-dependent RNA polymerase could represent another example, after carbonic anhydrase, histone deacetylase, and HIV-1 integrase, of metal binding as a successful strategy in drug design.	CONCL
186	191	metal	chemical	Inhibition of the endonuclease activity of influenza RNA-dependent RNA polymerase could represent another example, after carbonic anhydrase, histone deacetylase, and HIV-1 integrase, of metal binding as a successful strategy in drug design.	CONCL
15	20	water	chemical	The ligand and water molecules were discarded and the hydrogens were added to the protein by Discovery Studio 2.5.	METHODS
233	244	presence of	protein_state	One microgram of recombinant PA-Nter (residues 1–217 from the PA protein of influenza virus strain A/X-31) was incubated with 1 μg (16.7 nM) of single-stranded circular DNA plasmid M13mp18 (Bayou Biolabs, Metairie, Louisiana) in the presence of the test compounds and at a final volume of 25 μL. The assay buffer contained 50 mM Tris-HCl pH 8, 100 mM NaCl, 10 mM β-mercaptoethanol and 1 mM MnCl2.	METHODS
42	53	presence of	protein_state	After incubation at 37 °C for 24 h in the presence of serial dilutions of the test compounds, the ONE-Glo luciferase assay system (Promega, Madison, WI) was used to determine luciferase activity.	METHODS
53	57	EC99	evidence	The compound concentration values causing a 2-log10 (EC99) and a 1-log10 (EC90) reduction in viral RNA (vRNA) copy number at 24 h p.i., as compared to the virus control receiving no compound, were calculated by interpolation from data of at least three experiments.	METHODS
74	78	EC90	evidence	The compound concentration values causing a 2-log10 (EC99) and a 1-log10 (EC90) reduction in viral RNA (vRNA) copy number at 24 h p.i., as compared to the virus control receiving no compound, were calculated by interpolation from data of at least three experiments.	METHODS
17	25	PANΔLoop	mutant	A PAN construct (PANΔLoop) with a loop (residues 51–72) deleted and replaced with GGS from A/California/04/2009 H1N1 strain was used for the crystallographic studies.	METHODS
21	29	PANΔLoop	mutant	The apo structure of PANΔLoop (PDB ID: 5DES) was used as starting model for molecular replacement.	METHODS
52	61	influenza	taxonomy_domain	Chemical structures of some prototype inhibitors of influenza virus endonuclease.	FIG
62	67	virus	taxonomy_domain	Chemical structures of some prototype inhibitors of influenza virus endonuclease.	FIG
68	80	endonuclease	protein_type	Chemical structures of some prototype inhibitors of influenza virus endonuclease.	FIG
22	38	enzymatic assays	experimental_method	Inhibitor activity in enzymatic assays (IC50, μM) as reported in: aref., bref., cref., dref..	FIG
40	44	IC50	evidence	Inhibitor activity in enzymatic assays (IC50, μM) as reported in: aref., bref., cref., dref..	FIG
22	38	N-acylhydrazones	chemical	General synthesis for N-acylhydrazones 1–27 and hydrazides 28 and 29 (A).	FIG
39	43	1–27	chemical	General synthesis for N-acylhydrazones 1–27 and hydrazides 28 and 29 (A).	FIG
48	58	hydrazides	chemical	General synthesis for N-acylhydrazones 1–27 and hydrazides 28 and 29 (A).	FIG
59	61	28	chemical	General synthesis for N-acylhydrazones 1–27 and hydrazides 28 and 29 (A).	FIG
66	68	29	chemical	General synthesis for N-acylhydrazones 1–27 and hydrazides 28 and 29 (A).	FIG
33	37	1–27	chemical	Chemical structures of compounds 1–27 (B).	FIG
62	66	1–27	chemical	Overview of the structure-activity relationship for compounds 1–27.	FIG
48	64	N-acylhydrazones	chemical	Scheme of possible binding modes of the studied N-acylhydrazones.	FIG
25	44	GOLD cluster docked	experimental_method	First (A) and second (B) GOLD cluster docked solutions of compound 23 (orange and cyan, respectively) in complex with PA endonuclease.	FIG
67	69	23	chemical	First (A) and second (B) GOLD cluster docked solutions of compound 23 (orange and cyan, respectively) in complex with PA endonuclease.	FIG
102	117	in complex with	protein_state	First (A) and second (B) GOLD cluster docked solutions of compound 23 (orange and cyan, respectively) in complex with PA endonuclease.	FIG
118	120	PA	protein	First (A) and second (B) GOLD cluster docked solutions of compound 23 (orange and cyan, respectively) in complex with PA endonuclease.	FIG
121	133	endonuclease	protein_type	First (A) and second (B) GOLD cluster docked solutions of compound 23 (orange and cyan, respectively) in complex with PA endonuclease.	FIG
20	26	pocket	site	Key residues of the pocket are presented using PyMOL [ http://www.pymol.org] and LIGPLUS [Laskowski, R. A.; Swindells, M. B. Journal of chemical information and modeling 2011, 51, 2778].	FIG
81	88	LIGPLUS	experimental_method	Key residues of the pocket are presented using PyMOL [ http://www.pymol.org] and LIGPLUS [Laskowski, R. A.; Swindells, M. B. Journal of chemical information and modeling 2011, 51, 2778].	FIG
20	26	pocket	site	Key residues of the pocket are presented using PyMOL [ http://www.pymol.org] and LIGPLUS [Laskowski, R. A.; Swindells, M. B. Journal of chemical information and modeling 2011, 51, 2778].	FIG
81	88	LIGPLUS	experimental_method	Key residues of the pocket are presented using PyMOL [ http://www.pymol.org] and LIGPLUS [Laskowski, R. A.; Swindells, M. B. Journal of chemical information and modeling 2011, 51, 2778].	FIG
0	14	Hydrogen bonds	bond_interaction	Hydrogen bonds are illustrated by dotted lines, while the divalent metal ions are shown as purple spheres.	FIG
71	90	GOLD cluster docked	experimental_method	Schematic drawings of the interactions of the first (C) and second (D) GOLD cluster docked solutions generated using LIGPLUS.	FIG
117	124	LIGPLUS	experimental_method	Schematic drawings of the interactions of the first (C) and second (D) GOLD cluster docked solutions generated using LIGPLUS.	FIG
17	31	hydrogen bonds	bond_interaction	Dashed lines are hydrogen bonds and ‘eyelashes’ show residues involved in hydrophobic interactions.	FIG
74	98	hydrophobic interactions	bond_interaction	Dashed lines are hydrogen bonds and ‘eyelashes’ show residues involved in hydrophobic interactions.	FIG
17	31	hydrogen bonds	bond_interaction	Dashed lines are hydrogen bonds and ‘eyelashes’ show residues involved in hydrophobic interactions.	FIG
74	98	hydrophobic interactions	bond_interaction	Dashed lines are hydrogen bonds and ‘eyelashes’ show residues involved in hydrophobic interactions.	FIG
29	31	15	chemical	(A) Binding mode of compound 15 (orange) in complex with PA endonuclease.	FIG
41	56	in complex with	protein_state	(A) Binding mode of compound 15 (orange) in complex with PA endonuclease.	FIG
57	59	PA	protein	(A) Binding mode of compound 15 (orange) in complex with PA endonuclease.	FIG
60	72	endonuclease	protein_type	(A) Binding mode of compound 15 (orange) in complex with PA endonuclease.	FIG
0	14	Hydrogen bonds	bond_interaction	Hydrogen bonds are illustrated by dotted lines while the divalent metal ions are shown as purple spheres.	FIG
54	56	15	chemical	(B) Schematic drawing of the interactions of compound 15 generated using LIGPLUS.	FIG
73	80	LIGPLUS	experimental_method	(B) Schematic drawing of the interactions of compound 15 generated using LIGPLUS.	FIG
0	17	Crystal structure	evidence	Crystal structure of PANΔLoop in complex with compound 23.	FIG
21	29	PANΔLoop	mutant	Crystal structure of PANΔLoop in complex with compound 23.	FIG
30	45	in complex with	protein_state	Crystal structure of PANΔLoop in complex with compound 23.	FIG
55	57	23	chemical	Crystal structure of PANΔLoop in complex with compound 23.	FIG
0	11	Active site	site	Active site residues are shown in sticks with green carbons, manganese atoms are shown as purple spheres and water molecules as red spheres.	FIG
61	70	manganese	chemical	Active site residues are shown in sticks with green carbons, manganese atoms are shown as purple spheres and water molecules as red spheres.	FIG
109	114	water	chemical	Active site residues are shown in sticks with green carbons, manganese atoms are shown as purple spheres and water molecules as red spheres.	FIG
9	11	23	chemical	Compound 23 is shown in sticks with yellow carbons.	FIG
0	27	2Fo-Fc electron density map	evidence	2Fo-Fc electron density map contoured at 1σ is shown as blue mesh.	FIG
0	14	Hydrogen bonds	bond_interaction	Hydrogen bonds and metal coordination are shown with dotted lines.	FIG
19	37	metal coordination	bond_interaction	Hydrogen bonds and metal coordination are shown with dotted lines.	FIG
4	10	H-bond	bond_interaction	The H-bond distances from the side chain carboxyl group of Glu26 to p-OH and m-OH of the trihydroxyphenyl group of the inhibitor are 2.7 Å and 3.0 Å, respectively.	FIG
59	64	Glu26	residue_name_number	The H-bond distances from the side chain carboxyl group of Glu26 to p-OH and m-OH of the trihydroxyphenyl group of the inhibitor are 2.7 Å and 3.0 Å, respectively.	FIG
4	10	H-bond	bond_interaction	The H-bond distance from the side chain of Lys34 to p-OH of the trihydroxyphenyl group is 3.6 Å. The H-bond distance to the water molecule from m-OH of the galloyl moiety is 3.0 Å, which in turn is H-bonded to the side chain of Tyr130 with a distance of 2.7 Å. Crystal structure has been deposited in the RCSB Protein Data Bank with PDB ID: 5EGA.	FIG
43	48	Lys34	residue_name_number	The H-bond distance from the side chain of Lys34 to p-OH of the trihydroxyphenyl group is 3.6 Å. The H-bond distance to the water molecule from m-OH of the galloyl moiety is 3.0 Å, which in turn is H-bonded to the side chain of Tyr130 with a distance of 2.7 Å. Crystal structure has been deposited in the RCSB Protein Data Bank with PDB ID: 5EGA.	FIG
101	107	H-bond	bond_interaction	The H-bond distance from the side chain of Lys34 to p-OH of the trihydroxyphenyl group is 3.6 Å. The H-bond distance to the water molecule from m-OH of the galloyl moiety is 3.0 Å, which in turn is H-bonded to the side chain of Tyr130 with a distance of 2.7 Å. Crystal structure has been deposited in the RCSB Protein Data Bank with PDB ID: 5EGA.	FIG
124	129	water	chemical	The H-bond distance from the side chain of Lys34 to p-OH of the trihydroxyphenyl group is 3.6 Å. The H-bond distance to the water molecule from m-OH of the galloyl moiety is 3.0 Å, which in turn is H-bonded to the side chain of Tyr130 with a distance of 2.7 Å. Crystal structure has been deposited in the RCSB Protein Data Bank with PDB ID: 5EGA.	FIG
198	206	H-bonded	bond_interaction	The H-bond distance from the side chain of Lys34 to p-OH of the trihydroxyphenyl group is 3.6 Å. The H-bond distance to the water molecule from m-OH of the galloyl moiety is 3.0 Å, which in turn is H-bonded to the side chain of Tyr130 with a distance of 2.7 Å. Crystal structure has been deposited in the RCSB Protein Data Bank with PDB ID: 5EGA.	FIG
228	234	Tyr130	residue_name_number	The H-bond distance from the side chain of Lys34 to p-OH of the trihydroxyphenyl group is 3.6 Å. The H-bond distance to the water molecule from m-OH of the galloyl moiety is 3.0 Å, which in turn is H-bonded to the side chain of Tyr130 with a distance of 2.7 Å. Crystal structure has been deposited in the RCSB Protein Data Bank with PDB ID: 5EGA.	FIG
261	278	Crystal structure	evidence	The H-bond distance from the side chain of Lys34 to p-OH of the trihydroxyphenyl group is 3.6 Å. The H-bond distance to the water molecule from m-OH of the galloyl moiety is 3.0 Å, which in turn is H-bonded to the side chain of Tyr130 with a distance of 2.7 Å. Crystal structure has been deposited in the RCSB Protein Data Bank with PDB ID: 5EGA.	FIG
27	43	N-acylhydrazones	chemical	Inhibitory activity of the N-acylhydrazones 1–27 and hydrazide 28 in the enzymatic assay with influenza virus PA-Nter endonuclease, or in cellular influenza virus assays.	TABLE
44	48	1–27	chemical	Inhibitory activity of the N-acylhydrazones 1–27 and hydrazide 28 in the enzymatic assay with influenza virus PA-Nter endonuclease, or in cellular influenza virus assays.	TABLE
53	62	hydrazide	chemical	Inhibitory activity of the N-acylhydrazones 1–27 and hydrazide 28 in the enzymatic assay with influenza virus PA-Nter endonuclease, or in cellular influenza virus assays.	TABLE
63	65	28	chemical	Inhibitory activity of the N-acylhydrazones 1–27 and hydrazide 28 in the enzymatic assay with influenza virus PA-Nter endonuclease, or in cellular influenza virus assays.	TABLE
73	88	enzymatic assay	experimental_method	Inhibitory activity of the N-acylhydrazones 1–27 and hydrazide 28 in the enzymatic assay with influenza virus PA-Nter endonuclease, or in cellular influenza virus assays.	TABLE
94	103	influenza	taxonomy_domain	Inhibitory activity of the N-acylhydrazones 1–27 and hydrazide 28 in the enzymatic assay with influenza virus PA-Nter endonuclease, or in cellular influenza virus assays.	TABLE
104	109	virus	taxonomy_domain	Inhibitory activity of the N-acylhydrazones 1–27 and hydrazide 28 in the enzymatic assay with influenza virus PA-Nter endonuclease, or in cellular influenza virus assays.	TABLE
110	112	PA	protein	Inhibitory activity of the N-acylhydrazones 1–27 and hydrazide 28 in the enzymatic assay with influenza virus PA-Nter endonuclease, or in cellular influenza virus assays.	TABLE
113	117	Nter	structure_element	Inhibitory activity of the N-acylhydrazones 1–27 and hydrazide 28 in the enzymatic assay with influenza virus PA-Nter endonuclease, or in cellular influenza virus assays.	TABLE
118	130	endonuclease	protein_type	Inhibitory activity of the N-acylhydrazones 1–27 and hydrazide 28 in the enzymatic assay with influenza virus PA-Nter endonuclease, or in cellular influenza virus assays.	TABLE
138	169	cellular influenza virus assays	experimental_method	Inhibitory activity of the N-acylhydrazones 1–27 and hydrazide 28 in the enzymatic assay with influenza virus PA-Nter endonuclease, or in cellular influenza virus assays.	TABLE
0	21	"Compound	Enzyme assay"	experimental_method	"Compound	Enzyme assay with PA-Ntera	Virus yield assay in influenza virus-infected MDCK cellsb	vRNP reconstitution assay in HEK293T cellsc	 	Antiviral activity	Cytotoxicity	SId	Activity	Cytotoxicity	 	IC50	EC99	EC90	CC50	EC50	CC50	 	(1)	24	NDf	ND	ND	 	107	>200	 	(2)	>500	ND	ND	ND	 	>100	>200	 	(3)	>500	ND	ND	>200	 	5.9	48	 	(4)	>500	ND	ND	>200	 	6.3	33	 	(5)	67	>25	>25	≥146	 	2.6	10	 	(6)	>500	>50	>50	>200	 	15	14	 	(7)	54	172	100	>200	>2.0	3.2	8.9	 	(8)	>500	>12.5	>12.5	>200	 	1.9	15	 	(9)	34	16	5.3	>200	>38	5.5	>200	 	(10)	68	14	8.5	111	>13	0.40	132	 	(11)	45	30	12	>200	>17	5.6	>200	 	(12)	>500	>12.5	>12.5	>200	 	20	39	 	(13)	69	71	34	>200	>5.9	6.3	>200	 	(14)	>500	63	37	>200	>5.4	2.3	>200	 	(15)	8.9	18	7.5	≥172	≥23	14	>200	 	(16)	454	67	28	>200	>7.1	5.2	>200	 	(17)	482	21	8.1	>200	>25	7.1	>200	 	(18)	83	6.2	2.2	>200	>91	3.3	>200	 	(19)	>500	53	26	>200	>7.7	5.7	>200	 	(20)	18	35	11	>200	>18	2.2	>200	 	(21)	13	8.3	3.6	>200	>56	2.5	>200	 	(22)	75	7.4	3.4	>200	>59	0.42	>200	 	(23)	8.7	11	3.5	>200	>57	3.1	>200	 	(24)	131	58	26	>200	>7.7	25	>200	 	(25)	40	132	70	>200	>2.9	4.1	>200	 	(26)	30	36	13	>200	>15	5.5	>200	 	(27)	36	ND	ND	ND	 	21	>200	 	(28)	40	158	85	>200	>2.4	7.2	>200	 	DPBAe	5.3	ND	ND	ND	 	ND	ND	 	Ribavirin	ND	13	8.5	>200	>24	9.4	>200	 	"	TABLE
27	29	PA	protein	"Compound	Enzyme assay with PA-Ntera	Virus yield assay in influenza virus-infected MDCK cellsb	vRNP reconstitution assay in HEK293T cellsc	 	Antiviral activity	Cytotoxicity	SId	Activity	Cytotoxicity	 	IC50	EC99	EC90	CC50	EC50	CC50	 	(1)	24	NDf	ND	ND	 	107	>200	 	(2)	>500	ND	ND	ND	 	>100	>200	 	(3)	>500	ND	ND	>200	 	5.9	48	 	(4)	>500	ND	ND	>200	 	6.3	33	 	(5)	67	>25	>25	≥146	 	2.6	10	 	(6)	>500	>50	>50	>200	 	15	14	 	(7)	54	172	100	>200	>2.0	3.2	8.9	 	(8)	>500	>12.5	>12.5	>200	 	1.9	15	 	(9)	34	16	5.3	>200	>38	5.5	>200	 	(10)	68	14	8.5	111	>13	0.40	132	 	(11)	45	30	12	>200	>17	5.6	>200	 	(12)	>500	>12.5	>12.5	>200	 	20	39	 	(13)	69	71	34	>200	>5.9	6.3	>200	 	(14)	>500	63	37	>200	>5.4	2.3	>200	 	(15)	8.9	18	7.5	≥172	≥23	14	>200	 	(16)	454	67	28	>200	>7.1	5.2	>200	 	(17)	482	21	8.1	>200	>25	7.1	>200	 	(18)	83	6.2	2.2	>200	>91	3.3	>200	 	(19)	>500	53	26	>200	>7.7	5.7	>200	 	(20)	18	35	11	>200	>18	2.2	>200	 	(21)	13	8.3	3.6	>200	>56	2.5	>200	 	(22)	75	7.4	3.4	>200	>59	0.42	>200	 	(23)	8.7	11	3.5	>200	>57	3.1	>200	 	(24)	131	58	26	>200	>7.7	25	>200	 	(25)	40	132	70	>200	>2.9	4.1	>200	 	(26)	30	36	13	>200	>15	5.5	>200	 	(27)	36	ND	ND	ND	 	21	>200	 	(28)	40	158	85	>200	>2.4	7.2	>200	 	DPBAe	5.3	ND	ND	ND	 	ND	ND	 	Ribavirin	ND	13	8.5	>200	>24	9.4	>200	 	"	TABLE
36	53	Virus yield assay	experimental_method	"Compound	Enzyme assay with PA-Ntera	Virus yield assay in influenza virus-infected MDCK cellsb	vRNP reconstitution assay in HEK293T cellsc	 	Antiviral activity	Cytotoxicity	SId	Activity	Cytotoxicity	 	IC50	EC99	EC90	CC50	EC50	CC50	 	(1)	24	NDf	ND	ND	 	107	>200	 	(2)	>500	ND	ND	ND	 	>100	>200	 	(3)	>500	ND	ND	>200	 	5.9	48	 	(4)	>500	ND	ND	>200	 	6.3	33	 	(5)	67	>25	>25	≥146	 	2.6	10	 	(6)	>500	>50	>50	>200	 	15	14	 	(7)	54	172	100	>200	>2.0	3.2	8.9	 	(8)	>500	>12.5	>12.5	>200	 	1.9	15	 	(9)	34	16	5.3	>200	>38	5.5	>200	 	(10)	68	14	8.5	111	>13	0.40	132	 	(11)	45	30	12	>200	>17	5.6	>200	 	(12)	>500	>12.5	>12.5	>200	 	20	39	 	(13)	69	71	34	>200	>5.9	6.3	>200	 	(14)	>500	63	37	>200	>5.4	2.3	>200	 	(15)	8.9	18	7.5	≥172	≥23	14	>200	 	(16)	454	67	28	>200	>7.1	5.2	>200	 	(17)	482	21	8.1	>200	>25	7.1	>200	 	(18)	83	6.2	2.2	>200	>91	3.3	>200	 	(19)	>500	53	26	>200	>7.7	5.7	>200	 	(20)	18	35	11	>200	>18	2.2	>200	 	(21)	13	8.3	3.6	>200	>56	2.5	>200	 	(22)	75	7.4	3.4	>200	>59	0.42	>200	 	(23)	8.7	11	3.5	>200	>57	3.1	>200	 	(24)	131	58	26	>200	>7.7	25	>200	 	(25)	40	132	70	>200	>2.9	4.1	>200	 	(26)	30	36	13	>200	>15	5.5	>200	 	(27)	36	ND	ND	ND	 	21	>200	 	(28)	40	158	85	>200	>2.4	7.2	>200	 	DPBAe	5.3	ND	ND	ND	 	ND	ND	 	Ribavirin	ND	13	8.5	>200	>24	9.4	>200	 	"	TABLE
57	66	influenza	taxonomy_domain	"Compound	Enzyme assay with PA-Ntera	Virus yield assay in influenza virus-infected MDCK cellsb	vRNP reconstitution assay in HEK293T cellsc	 	Antiviral activity	Cytotoxicity	SId	Activity	Cytotoxicity	 	IC50	EC99	EC90	CC50	EC50	CC50	 	(1)	24	NDf	ND	ND	 	107	>200	 	(2)	>500	ND	ND	ND	 	>100	>200	 	(3)	>500	ND	ND	>200	 	5.9	48	 	(4)	>500	ND	ND	>200	 	6.3	33	 	(5)	67	>25	>25	≥146	 	2.6	10	 	(6)	>500	>50	>50	>200	 	15	14	 	(7)	54	172	100	>200	>2.0	3.2	8.9	 	(8)	>500	>12.5	>12.5	>200	 	1.9	15	 	(9)	34	16	5.3	>200	>38	5.5	>200	 	(10)	68	14	8.5	111	>13	0.40	132	 	(11)	45	30	12	>200	>17	5.6	>200	 	(12)	>500	>12.5	>12.5	>200	 	20	39	 	(13)	69	71	34	>200	>5.9	6.3	>200	 	(14)	>500	63	37	>200	>5.4	2.3	>200	 	(15)	8.9	18	7.5	≥172	≥23	14	>200	 	(16)	454	67	28	>200	>7.1	5.2	>200	 	(17)	482	21	8.1	>200	>25	7.1	>200	 	(18)	83	6.2	2.2	>200	>91	3.3	>200	 	(19)	>500	53	26	>200	>7.7	5.7	>200	 	(20)	18	35	11	>200	>18	2.2	>200	 	(21)	13	8.3	3.6	>200	>56	2.5	>200	 	(22)	75	7.4	3.4	>200	>59	0.42	>200	 	(23)	8.7	11	3.5	>200	>57	3.1	>200	 	(24)	131	58	26	>200	>7.7	25	>200	 	(25)	40	132	70	>200	>2.9	4.1	>200	 	(26)	30	36	13	>200	>15	5.5	>200	 	(27)	36	ND	ND	ND	 	21	>200	 	(28)	40	158	85	>200	>2.4	7.2	>200	 	DPBAe	5.3	ND	ND	ND	 	ND	ND	 	Ribavirin	ND	13	8.5	>200	>24	9.4	>200	 	"	TABLE
67	72	virus	taxonomy_domain	"Compound	Enzyme assay with PA-Ntera	Virus yield assay in influenza virus-infected MDCK cellsb	vRNP reconstitution assay in HEK293T cellsc	 	Antiviral activity	Cytotoxicity	SId	Activity	Cytotoxicity	 	IC50	EC99	EC90	CC50	EC50	CC50	 	(1)	24	NDf	ND	ND	 	107	>200	 	(2)	>500	ND	ND	ND	 	>100	>200	 	(3)	>500	ND	ND	>200	 	5.9	48	 	(4)	>500	ND	ND	>200	 	6.3	33	 	(5)	67	>25	>25	≥146	 	2.6	10	 	(6)	>500	>50	>50	>200	 	15	14	 	(7)	54	172	100	>200	>2.0	3.2	8.9	 	(8)	>500	>12.5	>12.5	>200	 	1.9	15	 	(9)	34	16	5.3	>200	>38	5.5	>200	 	(10)	68	14	8.5	111	>13	0.40	132	 	(11)	45	30	12	>200	>17	5.6	>200	 	(12)	>500	>12.5	>12.5	>200	 	20	39	 	(13)	69	71	34	>200	>5.9	6.3	>200	 	(14)	>500	63	37	>200	>5.4	2.3	>200	 	(15)	8.9	18	7.5	≥172	≥23	14	>200	 	(16)	454	67	28	>200	>7.1	5.2	>200	 	(17)	482	21	8.1	>200	>25	7.1	>200	 	(18)	83	6.2	2.2	>200	>91	3.3	>200	 	(19)	>500	53	26	>200	>7.7	5.7	>200	 	(20)	18	35	11	>200	>18	2.2	>200	 	(21)	13	8.3	3.6	>200	>56	2.5	>200	 	(22)	75	7.4	3.4	>200	>59	0.42	>200	 	(23)	8.7	11	3.5	>200	>57	3.1	>200	 	(24)	131	58	26	>200	>7.7	25	>200	 	(25)	40	132	70	>200	>2.9	4.1	>200	 	(26)	30	36	13	>200	>15	5.5	>200	 	(27)	36	ND	ND	ND	 	21	>200	 	(28)	40	158	85	>200	>2.4	7.2	>200	 	DPBAe	5.3	ND	ND	ND	 	ND	ND	 	Ribavirin	ND	13	8.5	>200	>24	9.4	>200	 	"	TABLE
94	119	vRNP reconstitution assay	experimental_method	"Compound	Enzyme assay with PA-Ntera	Virus yield assay in influenza virus-infected MDCK cellsb	vRNP reconstitution assay in HEK293T cellsc	 	Antiviral activity	Cytotoxicity	SId	Activity	Cytotoxicity	 	IC50	EC99	EC90	CC50	EC50	CC50	 	(1)	24	NDf	ND	ND	 	107	>200	 	(2)	>500	ND	ND	ND	 	>100	>200	 	(3)	>500	ND	ND	>200	 	5.9	48	 	(4)	>500	ND	ND	>200	 	6.3	33	 	(5)	67	>25	>25	≥146	 	2.6	10	 	(6)	>500	>50	>50	>200	 	15	14	 	(7)	54	172	100	>200	>2.0	3.2	8.9	 	(8)	>500	>12.5	>12.5	>200	 	1.9	15	 	(9)	34	16	5.3	>200	>38	5.5	>200	 	(10)	68	14	8.5	111	>13	0.40	132	 	(11)	45	30	12	>200	>17	5.6	>200	 	(12)	>500	>12.5	>12.5	>200	 	20	39	 	(13)	69	71	34	>200	>5.9	6.3	>200	 	(14)	>500	63	37	>200	>5.4	2.3	>200	 	(15)	8.9	18	7.5	≥172	≥23	14	>200	 	(16)	454	67	28	>200	>7.1	5.2	>200	 	(17)	482	21	8.1	>200	>25	7.1	>200	 	(18)	83	6.2	2.2	>200	>91	3.3	>200	 	(19)	>500	53	26	>200	>7.7	5.7	>200	 	(20)	18	35	11	>200	>18	2.2	>200	 	(21)	13	8.3	3.6	>200	>56	2.5	>200	 	(22)	75	7.4	3.4	>200	>59	0.42	>200	 	(23)	8.7	11	3.5	>200	>57	3.1	>200	 	(24)	131	58	26	>200	>7.7	25	>200	 	(25)	40	132	70	>200	>2.9	4.1	>200	 	(26)	30	36	13	>200	>15	5.5	>200	 	(27)	36	ND	ND	ND	 	21	>200	 	(28)	40	158	85	>200	>2.4	7.2	>200	 	DPBAe	5.3	ND	ND	ND	 	ND	ND	 	Ribavirin	ND	13	8.5	>200	>24	9.4	>200	 	"	TABLE
200	204	IC50	evidence	"Compound	Enzyme assay with PA-Ntera	Virus yield assay in influenza virus-infected MDCK cellsb	vRNP reconstitution assay in HEK293T cellsc	 	Antiviral activity	Cytotoxicity	SId	Activity	Cytotoxicity	 	IC50	EC99	EC90	CC50	EC50	CC50	 	(1)	24	NDf	ND	ND	 	107	>200	 	(2)	>500	ND	ND	ND	 	>100	>200	 	(3)	>500	ND	ND	>200	 	5.9	48	 	(4)	>500	ND	ND	>200	 	6.3	33	 	(5)	67	>25	>25	≥146	 	2.6	10	 	(6)	>500	>50	>50	>200	 	15	14	 	(7)	54	172	100	>200	>2.0	3.2	8.9	 	(8)	>500	>12.5	>12.5	>200	 	1.9	15	 	(9)	34	16	5.3	>200	>38	5.5	>200	 	(10)	68	14	8.5	111	>13	0.40	132	 	(11)	45	30	12	>200	>17	5.6	>200	 	(12)	>500	>12.5	>12.5	>200	 	20	39	 	(13)	69	71	34	>200	>5.9	6.3	>200	 	(14)	>500	63	37	>200	>5.4	2.3	>200	 	(15)	8.9	18	7.5	≥172	≥23	14	>200	 	(16)	454	67	28	>200	>7.1	5.2	>200	 	(17)	482	21	8.1	>200	>25	7.1	>200	 	(18)	83	6.2	2.2	>200	>91	3.3	>200	 	(19)	>500	53	26	>200	>7.7	5.7	>200	 	(20)	18	35	11	>200	>18	2.2	>200	 	(21)	13	8.3	3.6	>200	>56	2.5	>200	 	(22)	75	7.4	3.4	>200	>59	0.42	>200	 	(23)	8.7	11	3.5	>200	>57	3.1	>200	 	(24)	131	58	26	>200	>7.7	25	>200	 	(25)	40	132	70	>200	>2.9	4.1	>200	 	(26)	30	36	13	>200	>15	5.5	>200	 	(27)	36	ND	ND	ND	 	21	>200	 	(28)	40	158	85	>200	>2.4	7.2	>200	 	DPBAe	5.3	ND	ND	ND	 	ND	ND	 	Ribavirin	ND	13	8.5	>200	>24	9.4	>200	 	"	TABLE
205	209	EC99	evidence	"Compound	Enzyme assay with PA-Ntera	Virus yield assay in influenza virus-infected MDCK cellsb	vRNP reconstitution assay in HEK293T cellsc	 	Antiviral activity	Cytotoxicity	SId	Activity	Cytotoxicity	 	IC50	EC99	EC90	CC50	EC50	CC50	 	(1)	24	NDf	ND	ND	 	107	>200	 	(2)	>500	ND	ND	ND	 	>100	>200	 	(3)	>500	ND	ND	>200	 	5.9	48	 	(4)	>500	ND	ND	>200	 	6.3	33	 	(5)	67	>25	>25	≥146	 	2.6	10	 	(6)	>500	>50	>50	>200	 	15	14	 	(7)	54	172	100	>200	>2.0	3.2	8.9	 	(8)	>500	>12.5	>12.5	>200	 	1.9	15	 	(9)	34	16	5.3	>200	>38	5.5	>200	 	(10)	68	14	8.5	111	>13	0.40	132	 	(11)	45	30	12	>200	>17	5.6	>200	 	(12)	>500	>12.5	>12.5	>200	 	20	39	 	(13)	69	71	34	>200	>5.9	6.3	>200	 	(14)	>500	63	37	>200	>5.4	2.3	>200	 	(15)	8.9	18	7.5	≥172	≥23	14	>200	 	(16)	454	67	28	>200	>7.1	5.2	>200	 	(17)	482	21	8.1	>200	>25	7.1	>200	 	(18)	83	6.2	2.2	>200	>91	3.3	>200	 	(19)	>500	53	26	>200	>7.7	5.7	>200	 	(20)	18	35	11	>200	>18	2.2	>200	 	(21)	13	8.3	3.6	>200	>56	2.5	>200	 	(22)	75	7.4	3.4	>200	>59	0.42	>200	 	(23)	8.7	11	3.5	>200	>57	3.1	>200	 	(24)	131	58	26	>200	>7.7	25	>200	 	(25)	40	132	70	>200	>2.9	4.1	>200	 	(26)	30	36	13	>200	>15	5.5	>200	 	(27)	36	ND	ND	ND	 	21	>200	 	(28)	40	158	85	>200	>2.4	7.2	>200	 	DPBAe	5.3	ND	ND	ND	 	ND	ND	 	Ribavirin	ND	13	8.5	>200	>24	9.4	>200	 	"	TABLE
210	214	EC90	evidence	"Compound	Enzyme assay with PA-Ntera	Virus yield assay in influenza virus-infected MDCK cellsb	vRNP reconstitution assay in HEK293T cellsc	 	Antiviral activity	Cytotoxicity	SId	Activity	Cytotoxicity	 	IC50	EC99	EC90	CC50	EC50	CC50	 	(1)	24	NDf	ND	ND	 	107	>200	 	(2)	>500	ND	ND	ND	 	>100	>200	 	(3)	>500	ND	ND	>200	 	5.9	48	 	(4)	>500	ND	ND	>200	 	6.3	33	 	(5)	67	>25	>25	≥146	 	2.6	10	 	(6)	>500	>50	>50	>200	 	15	14	 	(7)	54	172	100	>200	>2.0	3.2	8.9	 	(8)	>500	>12.5	>12.5	>200	 	1.9	15	 	(9)	34	16	5.3	>200	>38	5.5	>200	 	(10)	68	14	8.5	111	>13	0.40	132	 	(11)	45	30	12	>200	>17	5.6	>200	 	(12)	>500	>12.5	>12.5	>200	 	20	39	 	(13)	69	71	34	>200	>5.9	6.3	>200	 	(14)	>500	63	37	>200	>5.4	2.3	>200	 	(15)	8.9	18	7.5	≥172	≥23	14	>200	 	(16)	454	67	28	>200	>7.1	5.2	>200	 	(17)	482	21	8.1	>200	>25	7.1	>200	 	(18)	83	6.2	2.2	>200	>91	3.3	>200	 	(19)	>500	53	26	>200	>7.7	5.7	>200	 	(20)	18	35	11	>200	>18	2.2	>200	 	(21)	13	8.3	3.6	>200	>56	2.5	>200	 	(22)	75	7.4	3.4	>200	>59	0.42	>200	 	(23)	8.7	11	3.5	>200	>57	3.1	>200	 	(24)	131	58	26	>200	>7.7	25	>200	 	(25)	40	132	70	>200	>2.9	4.1	>200	 	(26)	30	36	13	>200	>15	5.5	>200	 	(27)	36	ND	ND	ND	 	21	>200	 	(28)	40	158	85	>200	>2.4	7.2	>200	 	DPBAe	5.3	ND	ND	ND	 	ND	ND	 	Ribavirin	ND	13	8.5	>200	>24	9.4	>200	 	"	TABLE
215	219	CC50	evidence	"Compound	Enzyme assay with PA-Ntera	Virus yield assay in influenza virus-infected MDCK cellsb	vRNP reconstitution assay in HEK293T cellsc	 	Antiviral activity	Cytotoxicity	SId	Activity	Cytotoxicity	 	IC50	EC99	EC90	CC50	EC50	CC50	 	(1)	24	NDf	ND	ND	 	107	>200	 	(2)	>500	ND	ND	ND	 	>100	>200	 	(3)	>500	ND	ND	>200	 	5.9	48	 	(4)	>500	ND	ND	>200	 	6.3	33	 	(5)	67	>25	>25	≥146	 	2.6	10	 	(6)	>500	>50	>50	>200	 	15	14	 	(7)	54	172	100	>200	>2.0	3.2	8.9	 	(8)	>500	>12.5	>12.5	>200	 	1.9	15	 	(9)	34	16	5.3	>200	>38	5.5	>200	 	(10)	68	14	8.5	111	>13	0.40	132	 	(11)	45	30	12	>200	>17	5.6	>200	 	(12)	>500	>12.5	>12.5	>200	 	20	39	 	(13)	69	71	34	>200	>5.9	6.3	>200	 	(14)	>500	63	37	>200	>5.4	2.3	>200	 	(15)	8.9	18	7.5	≥172	≥23	14	>200	 	(16)	454	67	28	>200	>7.1	5.2	>200	 	(17)	482	21	8.1	>200	>25	7.1	>200	 	(18)	83	6.2	2.2	>200	>91	3.3	>200	 	(19)	>500	53	26	>200	>7.7	5.7	>200	 	(20)	18	35	11	>200	>18	2.2	>200	 	(21)	13	8.3	3.6	>200	>56	2.5	>200	 	(22)	75	7.4	3.4	>200	>59	0.42	>200	 	(23)	8.7	11	3.5	>200	>57	3.1	>200	 	(24)	131	58	26	>200	>7.7	25	>200	 	(25)	40	132	70	>200	>2.9	4.1	>200	 	(26)	30	36	13	>200	>15	5.5	>200	 	(27)	36	ND	ND	ND	 	21	>200	 	(28)	40	158	85	>200	>2.4	7.2	>200	 	DPBAe	5.3	ND	ND	ND	 	ND	ND	 	Ribavirin	ND	13	8.5	>200	>24	9.4	>200	 	"	TABLE
220	224	EC50	evidence	"Compound	Enzyme assay with PA-Ntera	Virus yield assay in influenza virus-infected MDCK cellsb	vRNP reconstitution assay in HEK293T cellsc	 	Antiviral activity	Cytotoxicity	SId	Activity	Cytotoxicity	 	IC50	EC99	EC90	CC50	EC50	CC50	 	(1)	24	NDf	ND	ND	 	107	>200	 	(2)	>500	ND	ND	ND	 	>100	>200	 	(3)	>500	ND	ND	>200	 	5.9	48	 	(4)	>500	ND	ND	>200	 	6.3	33	 	(5)	67	>25	>25	≥146	 	2.6	10	 	(6)	>500	>50	>50	>200	 	15	14	 	(7)	54	172	100	>200	>2.0	3.2	8.9	 	(8)	>500	>12.5	>12.5	>200	 	1.9	15	 	(9)	34	16	5.3	>200	>38	5.5	>200	 	(10)	68	14	8.5	111	>13	0.40	132	 	(11)	45	30	12	>200	>17	5.6	>200	 	(12)	>500	>12.5	>12.5	>200	 	20	39	 	(13)	69	71	34	>200	>5.9	6.3	>200	 	(14)	>500	63	37	>200	>5.4	2.3	>200	 	(15)	8.9	18	7.5	≥172	≥23	14	>200	 	(16)	454	67	28	>200	>7.1	5.2	>200	 	(17)	482	21	8.1	>200	>25	7.1	>200	 	(18)	83	6.2	2.2	>200	>91	3.3	>200	 	(19)	>500	53	26	>200	>7.7	5.7	>200	 	(20)	18	35	11	>200	>18	2.2	>200	 	(21)	13	8.3	3.6	>200	>56	2.5	>200	 	(22)	75	7.4	3.4	>200	>59	0.42	>200	 	(23)	8.7	11	3.5	>200	>57	3.1	>200	 	(24)	131	58	26	>200	>7.7	25	>200	 	(25)	40	132	70	>200	>2.9	4.1	>200	 	(26)	30	36	13	>200	>15	5.5	>200	 	(27)	36	ND	ND	ND	 	21	>200	 	(28)	40	158	85	>200	>2.4	7.2	>200	 	DPBAe	5.3	ND	ND	ND	 	ND	ND	 	Ribavirin	ND	13	8.5	>200	>24	9.4	>200	 	"	TABLE
225	229	CC50	evidence	"Compound	Enzyme assay with PA-Ntera	Virus yield assay in influenza virus-infected MDCK cellsb	vRNP reconstitution assay in HEK293T cellsc	 	Antiviral activity	Cytotoxicity	SId	Activity	Cytotoxicity	 	IC50	EC99	EC90	CC50	EC50	CC50	 	(1)	24	NDf	ND	ND	 	107	>200	 	(2)	>500	ND	ND	ND	 	>100	>200	 	(3)	>500	ND	ND	>200	 	5.9	48	 	(4)	>500	ND	ND	>200	 	6.3	33	 	(5)	67	>25	>25	≥146	 	2.6	10	 	(6)	>500	>50	>50	>200	 	15	14	 	(7)	54	172	100	>200	>2.0	3.2	8.9	 	(8)	>500	>12.5	>12.5	>200	 	1.9	15	 	(9)	34	16	5.3	>200	>38	5.5	>200	 	(10)	68	14	8.5	111	>13	0.40	132	 	(11)	45	30	12	>200	>17	5.6	>200	 	(12)	>500	>12.5	>12.5	>200	 	20	39	 	(13)	69	71	34	>200	>5.9	6.3	>200	 	(14)	>500	63	37	>200	>5.4	2.3	>200	 	(15)	8.9	18	7.5	≥172	≥23	14	>200	 	(16)	454	67	28	>200	>7.1	5.2	>200	 	(17)	482	21	8.1	>200	>25	7.1	>200	 	(18)	83	6.2	2.2	>200	>91	3.3	>200	 	(19)	>500	53	26	>200	>7.7	5.7	>200	 	(20)	18	35	11	>200	>18	2.2	>200	 	(21)	13	8.3	3.6	>200	>56	2.5	>200	 	(22)	75	7.4	3.4	>200	>59	0.42	>200	 	(23)	8.7	11	3.5	>200	>57	3.1	>200	 	(24)	131	58	26	>200	>7.7	25	>200	 	(25)	40	132	70	>200	>2.9	4.1	>200	 	(26)	30	36	13	>200	>15	5.5	>200	 	(27)	36	ND	ND	ND	 	21	>200	 	(28)	40	158	85	>200	>2.4	7.2	>200	 	DPBAe	5.3	ND	ND	ND	 	ND	ND	 	Ribavirin	ND	13	8.5	>200	>24	9.4	>200	 	"	TABLE
13	15	PA	protein	aRecombinant PA-Nter was incubated with the ssDNA plasmid substrate, a Mn2+-containing buffer and test compounds.	TABLE
16	20	Nter	structure_element	aRecombinant PA-Nter was incubated with the ssDNA plasmid substrate, a Mn2+-containing buffer and test compounds.	TABLE
25	34	incubated	experimental_method	aRecombinant PA-Nter was incubated with the ssDNA plasmid substrate, a Mn2+-containing buffer and test compounds.	TABLE
44	49	ssDNA	chemical	aRecombinant PA-Nter was incubated with the ssDNA plasmid substrate, a Mn2+-containing buffer and test compounds.	TABLE
71	75	Mn2+	chemical	aRecombinant PA-Nter was incubated with the ssDNA plasmid substrate, a Mn2+-containing buffer and test compounds.	TABLE
4	8	IC50	evidence	The IC50 represents the compound concentration (in μM) required to obtain 50% inhibition of cleavage, calculated by nonlinear least-squares regression analysis (using GraphPad Prism software) of the results from 2–4 independent experiments.	TABLE
116	159	nonlinear least-squares regression analysis	experimental_method	The IC50 represents the compound concentration (in μM) required to obtain 50% inhibition of cleavage, calculated by nonlinear least-squares regression analysis (using GraphPad Prism software) of the results from 2–4 independent experiments.	TABLE
31	42	influenza A	taxonomy_domain	bMDCK cells were infected with influenza A virus (strain A/PR/8/34) and incubated with the compounds during 24 h. The virus yield in the supernatant was assessed by real-time qPCR.	TABLE
43	48	virus	taxonomy_domain	bMDCK cells were infected with influenza A virus (strain A/PR/8/34) and incubated with the compounds during 24 h. The virus yield in the supernatant was assessed by real-time qPCR.	TABLE
118	123	virus	taxonomy_domain	bMDCK cells were infected with influenza A virus (strain A/PR/8/34) and incubated with the compounds during 24 h. The virus yield in the supernatant was assessed by real-time qPCR.	TABLE
165	179	real-time qPCR	experimental_method	bMDCK cells were infected with influenza A virus (strain A/PR/8/34) and incubated with the compounds during 24 h. The virus yield in the supernatant was assessed by real-time qPCR.	TABLE
4	8	EC99	evidence	The EC99 and EC90 values represent the compound concentrations (in μM) producing a 2-log10 or 1-log10 reduction in virus titer, respectively, determined in 2–3 independent experiments.	TABLE
13	17	EC90	evidence	The EC99 and EC90 values represent the compound concentrations (in μM) producing a 2-log10 or 1-log10 reduction in virus titer, respectively, determined in 2–3 independent experiments.	TABLE
115	120	virus	taxonomy_domain	The EC99 and EC90 values represent the compound concentrations (in μM) producing a 2-log10 or 1-log10 reduction in virus titer, respectively, determined in 2–3 independent experiments.	TABLE
74	78	CC50	evidence	The cytotoxicity, assessed in uninfected MDCK cells, was expressed as the CC50 value (50% cytotoxic concentration, determined with the MTS cell viability assay, in μM).	TABLE
135	159	MTS cell viability assay	experimental_method	The cytotoxicity, assessed in uninfected MDCK cells, was expressed as the CC50 value (50% cytotoxic concentration, determined with the MTS cell viability assay, in μM).	TABLE
20	34	co-transfected	experimental_method	cHEK293T cells were co-transfected with the four vRNP-reconstituting plasmids and the luciferase reporter plasmid in the presence of the test compounds.	TABLE
49	53	vRNP	complex_assembly	cHEK293T cells were co-transfected with the four vRNP-reconstituting plasmids and the luciferase reporter plasmid in the presence of the test compounds.	TABLE
121	132	presence of	protein_state	cHEK293T cells were co-transfected with the four vRNP-reconstituting plasmids and the luciferase reporter plasmid in the presence of the test compounds.	TABLE
4	8	EC50	evidence	The EC50 represents the compound concentration (in μM) producing 50% reduction in vRNP-driven firefly reporter signal, estimated at 24 h after transfection.	TABLE
82	86	vRNP	complex_assembly	The EC50 represents the compound concentration (in μM) producing 50% reduction in vRNP-driven firefly reporter signal, estimated at 24 h after transfection.	TABLE
4	8	EC50	evidence	The EC50 value was derived from data from 2–4 independent experiments, by nonlinear least-squares regression analysis (using GraphPad Prism software).	TABLE
74	117	nonlinear least-squares regression analysis	experimental_method	The EC50 value was derived from data from 2–4 independent experiments, by nonlinear least-squares regression analysis (using GraphPad Prism software).	TABLE
4	8	CC50	evidence	The CC50 (in μM), i.e. the 50% cytotoxic concentration, was determined in untransfected HEK293T cells by MTS cell viability assay.	TABLE
105	129	MTS cell viability assay	experimental_method	The CC50 (in μM), i.e. the 50% cytotoxic concentration, was determined in untransfected HEK293T cells by MTS cell viability assay.	TABLE
0	3	dSI	evidence	dSI, selectivity index, defined as the ratio between the CC50 and EC90.	TABLE
5	22	selectivity index	evidence	dSI, selectivity index, defined as the ratio between the CC50 and EC90.	TABLE
57	61	CC50	evidence	dSI, selectivity index, defined as the ratio between the CC50 and EC90.	TABLE
66	70	EC90	evidence	dSI, selectivity index, defined as the ratio between the CC50 and EC90.	TABLE
0	5	eDPBA	chemical	eDPBA, 2,4-dioxo-4-phenylbutanoic acid.	TABLE
7	38	2,4-dioxo-4-phenylbutanoic acid	chemical	eDPBA, 2,4-dioxo-4-phenylbutanoic acid.	TABLE