Phosphodiesterase (PDE) that catalyzes the hydrolysis of cyclic diguanylate (c-di-GMP) to GMP (PubMed:19170727, PubMed:24066157). Hydrolyzes c-di-GMP to GMP in a two-step reaction, via the linear intermediate 5'-phosphoguanylyl(3'->5')guanosine (pGpG). In vitro, can use pGpG as an alternative substrate and hydrolyze it into GMP (PubMed:24066157). Acts in regulation of motility, synthesis of virulence determinants and biofilm architecture (PubMed:19170727). May act preferentially as a pGpG binding protein (PubMed:24066157). cyclic di-3',5'-guanylate + 2 H2O = 2 GMP + 2 H(+) Phosphodiesterase activity is activated by phosphorylation of the N-terminal regulatory domain. Phosphorylation triggers a conformational change of the HD-GYP domain, which renders the active site accessible. kcat is 0.0002 sec(-1). Homodimer. Contains an unselective bimetallic binding site, with a high-affinity site (H-site) and a low-affinity site (L-site). Metal binding to the H-site triggers the binding to the L-site. This bimetallic center may play a structural more than a catalytic role. Phosphorylated. Disruption mutant has increased levels of cyclic di-GMP. Mutation leads to reduction in both swarming and twitching motility, to an increase in pyoverdine production, and a reduction in virulence. It produces a biofilm with little heterogeneity.