Mechanistic insights into c-di-GMP–dependent control of the biofilm regulator FleQ from Pseudomonas aeruginosa
- Departamento de Física e Ciência Interdisciplinar, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos 13563-120, SP, Brazil,
- Department of Structural Biology and Chemistry, Unité G5 Biologie Structurale de la Sécrétion Bactérienne and UMR 3528, CNRS, Institut Pasteur, 75015 Paris, France,, Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853,
- Department of Microbiology, University of Washington, Seattle, WA 98195
- Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853,
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 σ54-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.
- Research Organization:
- Cornell Univ., Ithaca, NY (United States); Univ. of Washington, Seattle, WA (United States); Univ. of Sao Paulo, Sao Carlos (Brazil)
- Sponsoring Organization:
- USDOE Office of Science (SC); National Science Foundation (NSF); National Inst. of Health (NIH) (United States); European Research Council (ERC); São Paulo Research Foundation (Brazil)
- Contributing Organization:
- Pasteur Inst., Paris (France)
- Grant/Contract Number:
- AC02-06CH11357; DMR-1332208; GM-103485; P41-GM103403; 2009/13238-0; 2011/24168-2; R01-AI097307; R01-GM56665
- OSTI ID:
- 1235512
- Alternate ID(s):
- OSTI ID: 1235479
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America, Journal Name: Proceedings of the National Academy of Sciences of the United States of America Vol. 113 Journal Issue: 2; ISSN 0027-8424
- Publisher:
- Proceedings of the National Academy of SciencesCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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