sentence: Genetic screening identified that loss of PelABDEG and the PA1120 protein ( which contains a GGDEF-motif ) suppressed the phenotypes of the PA3885 mutant , suggesting that the function of the PA3885 protein is to regulate 3,5 - cyclic diguanylic acid ( c-di-GMP ) concentrations as a phosphatase since c-di-GMP enhances biofilm formation by activating PelD , and c-di-GMP inhibits swarming .