4zhu
From Proteopedia
Crystal structure of a bacterial repressor protein
Structural highlights
FunctionYFIR_PSEAE Negatively regulates the activity of the diguanylate cyclase TpbB/YfiN, leading to decreased c-di-GMP production (PubMed:20300602). Inhibits TpbB/YfiN allosterically, through a hydrophobic interaction between the C-terminus of YfiR and a conserved region of the periplasmic PAS domain of TpbB/YfiN (PubMed:22719254). Under reducing conditions, may also act as an YfiB-independent sensing device that is able to activate TpbB/YfiN in response to the redox status of the periplasm (PubMed:22719254).[1] [2] Part of the YfiB-TpbB-YfiR (or yfiBNR) system, encoding a tripartite signaling module that modulates intracellular c-di-GMP levels (PubMed:20300602, PubMed:22719254). The system is a key regulator of the small colony variant (SCV) phenotype, and plays an important role in biofilm formation and in vivo persistence (PubMed:20300602). The c-di-GMP produced by TpbB/YfiN stimulates the production of the Pel and Psl exopolysaccharides, which promotes surface attachment, generates an SCV phenotype and confers resistance against phagocytosis (PubMed:20300602).[3] [4] Publication Abstract from PubMedYfiBNR is a tripartite signalling system in Pseudomonas aeruginosa that modulates intracellular c-di-GMP levels in response to signals received in the periplasm. YfiB is an outer membrane lipoprotein and presumed sensor protein that sequesters the repressor protein YfiR. To provide insights into YfiBNR function, we have determined three-dimensional crystal structures of YfiB and YfiR from P. aeruginosa PAO1 alone and as a 1:1 complex. A YfiB(27-168) construct is predominantly dimeric, whereas a YfiB(59-168) is monomeric, indicating that YfiB can dimerize via its N-terminal region. YfiR forms a stable complex with YfiB(59-168), while the YfiR binding interface is obstructed by the N-terminal region in YfiB(27-168). The YfiB-YfiR complex reveals a conserved interaction surface on YfiR that overlaps with residues predicted to interact with the periplasmic PAS domain of YfiN. Comparison of native and YfiR-bound structures of YfiB suggests unwinding of the N-terminal linker region for attachment to the outer membrane. A model is thus proposed for YfiR sequestration at the outer membrane by YfiB. Our work provides the first detailed insights into the interaction between YfiB and YfiR at the molecular level and is a valuable starting point for further functional and mechanistic studies of the YfiBNR signalling system. Structural insights into YfiR sequestering by YfiB in Pseudomonas aeruginosa PAO1.,Li S, Li T, Xu Y, Zhang Q, Zhang W, Che S, Liu R, Wang Y, Bartlam M Sci Rep. 2015 Nov 23;5:16915. doi: 10.1038/srep16915. PMID:26593397[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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