Genetic dissection of a motility-associated c-di-GMP signalling protein of Pseudomonas putida

SOFIA ÖSTERBERG; ANNA ÅBERG; M KARINA HERRERA SEITZ; MAGNUS WOLF-WATZ; VICTORIA SHINGLER

Environmental Microbiology Reports

Society for Applied Microbiology and Blackwell publishing

Año: 2013 vol. 5 p. 556 - 565

1758-2229

Lack of the Pseudomonas putida PP2258 protein or its overexpression results in defective motility on solid media. The PP2258 protein is tripartite, possessing a PAS domain linked to two domains associated with turnover of c-di-GMP ? a cyclic nucleotide that controls the switch between motile and sessile lifestyles. The second messenger c-di-GMP is produced by diguanylate cyclases and degraded by phosphodiesterases containing GGDEF and EAL or HD-GYP domains respectively. It is common for enzymes involved in c-di-GMP signalling to contain two domains with potentially opposing c-di-GMP turnover activities; however, usually one is degenerate and has been adopted to serve regulatory functions. Only a few proteins have previously been found to have dual enzymatic activities ? being capable of both synthesizing and hydrolysing c-di-GMP. Here, using truncated and mutant derivatives of PP2258, we show that despite a lack of complete consensus in either the GGDEF or EAL motifs, the two c-di-GMP turnover domains can function independently of each other, and that the diguanylate cyclase activity is regulated by an inhibitory I-site within its GGDEF domain. Thus, motility-associated PP2258 can be added to the short list of bifunctional c-di-GMP signalling proteins.