This domain is found linked to a wide range of non-homologous domains in a variety of bacteria. It has been shown to be homologous to the adenylyl cyclase catalytic domain [1] and has diguanylate cyclase activity [4]. This observation correlates with the functional information available on two GGDEF-containing proteins, namely diguanylate cyclase and phosphodiesterase A of Acetobacter xylinum, both of which regulate the turnover of cyclic diguanosine monophosphate. In the WspR protein of Pseudomonas aeruginosa, the GGDEF domain acts as a diguanylate cyclase, PDB:3bre, when the whole molecule appears to form a tetramer consisting of two symmetrically-related dimers representing a biological unit. The active site is the GGD/EF motif, buried in the structure, and the cyclic dimeric guanosine monophosphate (c-di-GMP) bind to the inhibitory-motif RxxD on the surface. The enzyme thus catalyses the cyclisation of two guanosine triphosphate (GTP) molecules to one c-di-GMP molecule [6,7,8].

1: GGDEF domain is homologous to adenylyl cyclase. Pei J, Grishin NV; Proteins 2001;42:210-216. PMID:11119645

2: Novel domains of the prokaryotic two-component signal transduction systems. Galperin MY, Nikolskaya AN, Koonin EV; FEMS Microbiol Lett 2001;203:11-21. PMID:11557134

3: Cyclic di-guanosine-monophosphate comes of age: a novel secondary messenger involved in modulating cell surface structures in bacteria?. Jenal U; Curr Opin Microbiol 2004;7:185-191. PMID:15063857

4: Cell cycle-dependent dynamic localization of a bacterial response regulator with a novel di-guanylate cyclase output domain. Paul R, Weiser S, Amiot NC, Chan C, Schirmer T, Giese B, Jenal U; Genes Dev 2004;18:715-727. PMID:15075296

5: Bacterial signal transduction network in a genomic perspective. Galperin MY; Environ Microbiol 2004;6:552-567. PMID:15142243

6: Structural basis of activity and allosteric control of diguanylate cyclase. Chan C, Paul R, Samoray D, Amiot NC, Giese B, Jenal U, Schirmer T; Proc Natl Acad Sci U S A 2004;101:17084-17089. PMID:15569936

7: Allosteric control of cyclic di-GMP signaling. Christen B, Christen M, Paul R, Schmid F, Folcher M, Jenoe P, Meuwly M, Jenal U; J Biol Chem. 2006;281:32015-32024. PMID:16923812

8: Phosphorylation-independent regulation of the diguanylate cyclase WspR. De N, Pirruccello M, Krasteva PV, Bae N, Raghavan RV, Sondermann H; PLoS Biol. 2008;6:e67. PMID:18366254

9: The atypical two-component sensor kinase Lpl0330 from Legionella pneumophila controls the bifunctional diguanylate cyclase-phosphodiesterase Lpl0329 to modulate bis-(3'-5')-cyclic dimeric GMP synthesis. Levet-Paulo M, Lazzaroni JC, Gilbert C, Atlan D, Doublet P, Vianney A; J Biol Chem. 2011;286:31136-31144. PMID:21757706