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PDBsum entry 5exs
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Transcription
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PDB id
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5exs
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References listed in PDB file
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Key reference
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Title
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Mechanistic insights into c-Di-Gmp-Dependent control of the biofilm regulator fleq from pseudomonas aeruginosa.
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Authors
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B.Y.Matsuyama,
P.V.Krasteva,
C.Baraquet,
C.S.Harwood,
H.Sondermann,
M.V.Navarro.
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Ref.
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Proc Natl Acad Sci U S A, 2016,
113,
E209.
[DOI no: ]
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PubMed id
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Abstract
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Bacterial biofilm formation during chronic infections confers increased fitness,
antibiotic tolerance, and cytotoxicity. In many pathogens, the transition from a
planktonic lifestyle to collaborative, sessile biofilms represents a regulated
process orchestrated by the intracellular second-messenger c-di-GMP. A main
effector for c-di-GMP signaling in the opportunistic pathogen Pseudomonas
aeruginosa is the transcription regulator FleQ. FleQ is a bacterial
enhancer-binding protein (bEBP) with a central AAA+ ATPase σ(54)-interaction
domain, flanked by a C-terminal helix-turn-helix DNA-binding motif and a
divergent N-terminal receiver domain. Together with a second ATPase, FleN, FleQ
regulates the expression of flagellar and exopolysaccharide biosynthesis genes
in response to cellular c-di-GMP. Here we report structural and functional data
that reveal an unexpected mode of c-di-GMP recognition that is associated with
major conformational rearrangements in FleQ. Crystal structures of FleQ's AAA+
ATPase domain in its apo-state or bound to ADP or ATP-γ-S show conformations
reminiscent of the activated ring-shaped assemblies of other bEBPs. As revealed
by the structure of c-di-GMP-complexed FleQ, the second messenger interacts with
the AAA+ ATPase domain at a site distinct from the ATP binding pocket. c-di-GMP
interaction leads to active site obstruction, hexameric ring destabilization,
and discrete quaternary structure transitions. Solution and cell-based studies
confirm coupling of the ATPase active site and c-di-GMP binding, as well as the
functional significance of crystallographic interprotomer interfaces. Taken
together, our data offer unprecedented insight into conserved regulatory
mechanisms of gene expression under direct c-di-GMP control via FleQ and
FleQ-like bEBPs.
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