6hc0
Bdellovibrio bacteriovorus DgcB FHA domain, tail complexBdellovibrio bacteriovorus DgcB FHA domain, tail complex
Structural highlights
Publication Abstract from PubMedThe bacterial second messenger cyclic-di-GMP is a widespread, prominent effector of lifestyle change. An example of this occurs in the predatory bacterium Bdellovibrio bacteriovorus, which cycles between free-living and intraperiplasmic phases after entering (and killing) another bacterium. The initiation of prey invasion is governed by DgcB (GGDEF enzyme) that produces cyclic-di-GMP in response to an unknown stimulus. Here, we report the structure of DgcB, and demonstrate that the GGDEF and sensory forkhead-associated (FHA) domains form an asymmetric dimer. Our structures indicate that the FHA domain is a consensus phosphopeptide sensor, and that the ligand for activation is surprisingly derived from the N-terminal region of DgcB itself. We confirm this hypothesis by determining the structure of a FHA:phosphopeptide complex, from which we design a constitutively-active mutant (confirmed via enzyme assays). Our results provide an understanding of the stimulus driving DgcB-mediated prey invasion and detail a unique mechanism of GGDEF enzyme regulation. Structural basis for activation of a diguanylate cyclase required for bacterial predation in Bdellovibrio.,Meek RW, Cadby IT, Moynihan PJ, Lovering AL Nat Commun. 2019 Sep 9;10(1):4086. doi: 10.1038/s41467-019-12051-6. PMID:31501441[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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