title: GGDEF proteins YeaI, YedQ, and YfiN reduce early biofilm formation and swimming motility in Escherichia coli.
abstract: The second messenger 3'-5'-cyclic diguanylic acid (c-di-GMP) promotes biofilm formation, and c-di-GMP is synthesized by diguanylate cyclases (characterized by a GGDEF domain) and degraded by phosphodiesterases. Here, we evaluated the effect of the 12 E. coli GGDEF-only proteins on biofilm formation and motility. Deletions of the genes encoding the GGDEF proteins YeaI, YedQ, YfiN, YeaJ, and YneF increased swimming motility as expected for strains with reduced c-di-GMP. Alanine substitution in the EGEVF motif of YeaI abolished its impact on swimming motility. In addition, extracellular DNA (eDNA) was increased as expected for the deletions of yeaI (tenfold), yedQ (1.8-fold), and yfiN (3.2-fold). As a result of the significantly enhanced motility, but contrary to current models of decreased biofilm formation with decreased diguanylate cyclase activity, early biofilm formation increased dramatically for the deletions of yeaI (30-fold), yedQ (12-fold), and yfiN (18-fold). Our results indicate that YeaI, YedQ, and YfiN are active diguanylate cyclases that reduce motility, eDNA, and early biofilm formation and contrary to the current paradigm, the results indicate that c-di-GMP levels should be reduced, not increased, for initial biofilm formation so c-di-GMP levels must be regulated in a temporal fashion in biofilms.
authors.affiliation: Department of Chemical Engineering, Texas A & M University, 220 Jack E. Brown Building, College Station, TX 77843-3122, USA.
authors.forename: Viviana
authors.initials: V
authors.lastname: Sanchez-Torres
authors.forename: Hongbo
authors.initials: H
authors.lastname: Hu
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Wood
mesh_terms: D018441:Biofilms; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D016297:Mutagenesis, Site-Directed; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D019761:Phosphorus-Oxygen Lyases / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D015290:Second Messenger Systems
chemical_list: D029968:Escherichia coli Proteins; C062025:bis(3',5')-cyclic diguanylic acid; D010727:Phosphoric Diester Hydrolases; D019761:Phosphorus-Oxygen Lyases; C060720:diguanylate cyclase; D006152:Cyclic GMP