Structures of the PelD Cyclic Diguanylate Effector Involved in Pellicle Formation in Pseudomonas aeruginosa PAO1.Li, Z., Chen, J.H., Hao, Y., Nair, S.K.
(2012) J Biol Chem 287: 30191-30204
- PubMed: 22810222
- DOI: https://doi.org/10.1074/jbc.M112.378273
- Primary Citation of Related Structures:
4ETX, 4ETZ, 4EU0, 4EUV
- PubMed Abstract:
The second messenger bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) plays a vital role in the global regulation in bacteria. Here, we describe structural and biochemical characterization of a novel c-di-GMP effector PelD that is critical to the formation of pellicles by Pseudomonas aeruginosa. We present high-resolution structures of a cytosolic fragment of PelD in apo form and its complex with c-di-GMP. The structure contains a bi-domain architecture composed of a GAF domain (commonly found in cyclic nucleotide receptors) and a GGDEF domain (found in c-di-GMP synthesizing enzymes), with the latter binding to one molecule of c-di-GMP. The GGDEF domain has a degenerate active site but a conserved allosteric site (I-site), which we show binds c-di-GMP with a K(d) of 0.5 μm. We identified a series of residues that are crucial for c-di-GMP binding, and confirmed the roles of these residues through biochemical characterization of site-specific variants. The structures of PelD represent a novel class of c-di-GMP effector and expand the knowledge of scaffolds that mediate c-di-GMP recognition.
Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.