sentence: Amino-acid sequence alignments indicated that the PF1383 protein lacks some important amino-acid residues that are critical for the AP endonuclease activity , as shown in this study for PF0258 , although the total sequence similarities with E. coli Nfo are 13.5 % and 13.1 % for PF0258 and PF1383 , respectively ( Figure 1A ) .