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Sahoo PK, Sheenu, Jain D. REC domain stabilizes the active heptamer of σ 54-dependent transcription factor, FleR from Pseudomonas aeruginosa. iScience 2023; 26:108397. [PMID: 38058307 PMCID: PMC10696123 DOI: 10.1016/j.isci.2023.108397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 09/12/2023] [Accepted: 11/02/2023] [Indexed: 12/08/2023] Open
Abstract
Motility in Pseudomonas aeruginosa is mediated through a single, polar flagellum, which is essential for virulence, colonization, and biofilm formation. FleSR, a two-component system (TCS), serves as a critical checkpoint in flagellar assembly. FleR is a σ54-dependent response regulator that undergoes phosphorylation via cognate sensor kinase FleS for the assembly of the functionally active form. The active form remodels the σ54-RNAP complex to initiate transcription. Small-angle X-ray scattering, crystallography, and negative staining electron microscopy reconstructions of FleR revealed that it exists predominantly as a dimer in the inactive form with low ATPase activity and assembles into heptamers upon phosphorylation with amplified ATPase activity. We establish that receiver (REC) domain stabilizes the heptamers and is indispensable for assembly of the functional phosphorylated form of FleR. The structural, biochemical, and in vivo complementation assays provide details of the phosphorylation-mediated assembly of FleR to regulate the expression of flagellar genes.
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Affiliation(s)
- Pankaj Kumar Sahoo
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
| | - Sheenu
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
| | - Deepti Jain
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
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Chanchal, Banerjee P, Raghav S, Goswami HN, Jain D. The antiactivator FleN uses an allosteric mechanism to regulate σ 54-dependent expression of flagellar genes in Pseudomonas aeruginosa. SCIENCE ADVANCES 2021; 7:eabj1792. [PMID: 34669473 PMCID: PMC8528422 DOI: 10.1126/sciadv.abj1792] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 08/24/2021] [Indexed: 12/09/2023]
Abstract
Diverse sigma factors associate with the RNA polymerase (RNAP) core enzyme to initiate transcription of specific target genes in bacteria. σ54-Mediated transcription uses AAA+ activators that utilize their ATPase activity for transcription initiation. FleQ is a σ54-dependent master transcriptional regulator of flagellar genes in Pseudomonas aeruginosa. The ATPase activity of FleQ is regulated via a P-loop ATPase, FleN, through protein-protein interaction. We report a high-resolution crystal structure of the AAA+ domain of FleQ in complex with antiactivator FleN. The data reveal that FleN allosterically prevents ATP binding to FleQ. Furthermore, FleN remodels the region of FleQ essential for engagement with σ54 for transcription initiation. Disruption of the conserved protein-protein interface, by mutation, shows motility and transcription defects in vivo and multiflagellate phenotype. Our study provides a detailed mechanism used by monoflagellate bacteria to fine-tune the expression of flagellar genes to form and maintain a single flagellum.
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Affiliation(s)
- Chanchal
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3 Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
- Manipal Academy of Higher Education, Karnataka 576104, India
| | - Priyajit Banerjee
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3 Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
- Kalinga Institute of Industrial Technology, Bhubaneswar, Odisha 751024, India
| | - Shikha Raghav
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3 Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
| | - Hemant N. Goswami
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3 Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
| | - Deepti Jain
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3 Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
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Banerjee P, Sahoo PK, Sheenu, Adhikary A, Ruhal R, Jain D. Molecular and structural facets of c-di-GMP signalling associated with biofilm formation in Pseudomonas aeruginosa. Mol Aspects Med 2021; 81:101001. [PMID: 34311995 DOI: 10.1016/j.mam.2021.101001] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/09/2021] [Accepted: 07/16/2021] [Indexed: 12/29/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen and is the primary cause of nosocomial infections. Biofilm formation by this organism results in chronic and hard to eradicate infections. The intracellular signalling molecule bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a secondary messenger in bacterial cells crucial for motile to sessile transition. The signalling pathway components encompass two classes of enzymes with antagonistic activities, the diguanylate cyclases (DGCs) and phosphodiesterases (PDEs) that regulate the cellular levels of c-di-GMP at distinct stages of biofilm initiation, maturation and dispersion. This review summarizes the structural analysis and functional studies of the DGCs and PDEs involved in biofilm regulation in P. aeruginosa. In addition, we also describe the effector proteins that sense the perturbations in c-di-GMP levels to elicit a functional output. Finally, we discuss possible mechanisms that allow the dynamic levels of c-di-GMP to regulate cognate cellular response. Uncovering the details of the regulation of the c-di-GMP signalling pathway is vital for understanding the behaviour of the pathogen and characterization of novel targets for anti-biofilm interventions.
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Affiliation(s)
- Priyajit Banerjee
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, India; Kalinga Institute of Industrial Technology, Bhubaneswar, Odisha, 751024, India
| | - Pankaj Kumar Sahoo
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, India
| | - Sheenu
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, India
| | - Anirban Adhikary
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, India
| | - Rohit Ruhal
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, India
| | - Deepti Jain
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, India.
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Banerjee P, Chanchal, Jain D. Sensor I Regulated ATPase Activity of FleQ Is Essential for Motility to Biofilm Transition in Pseudomonas aeruginosa. ACS Chem Biol 2019; 14:1515-1527. [PMID: 31268665 DOI: 10.1021/acschembio.9b00255] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Members of the AAA+ (ATPase associated with various cellular activities) family of ATPases couple chemical energy derived from ATP hydrolysis for generation of mechanical force, resulting in conformational changes. The hydrolysis is brought about by highly conserved domains and motifs. The sensor I motif is critical for sensing and hydrolysis of the nucleotide. Pseudomonas aeruginosa FleQ is an ATPase that is a positive regulator of flagellar gene expression. We have determined the crystal structures of the ATPase domain of wild-type FleQ and sensor I mutants H287N and H287A in complex with ATPγS and Mg2+ to 2.4, 1.95, and 2.25 Å resolution, respectively. The structural data highlight the role of sensor I in regulating the ATPase activity. The in vitro and in vivo data demonstrate that the moderate ATPase activity of FleQ due to the presence of histidine in sensor I is essential for maintaining the monotrichous phenotype and for the rapid motility to biofilm transition.
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Affiliation(s)
- Priyajit Banerjee
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
- Kalinga Institute of Industrial Technology, Bhubaneswar, Odisha 751024, India
| | - Chanchal
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
- Manipal Academy of Higher Education, Karnataka 576104, India
| | - Deepti Jain
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
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Chanchal, Banerjee P, Jain D. ATP-Induced Structural Remodeling in the Antiactivator FleN Enables Formation of the Functional Dimeric Form. Structure 2017; 25:243-252. [PMID: 28065505 DOI: 10.1016/j.str.2016.11.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 09/09/2016] [Accepted: 11/28/2016] [Indexed: 10/20/2022]
Abstract
FleN, a P loop ATPase is vital for maintaining a monotrichous phenotype in Pseudomonas aeruginosa. FleN exhibits antagonistic activity against FleQ, the master transcriptional regulator of flagellar genes. Crystal structures of FleN in the apo form (1.66 Å) and in complex with β,γ-imidoadenosine 5'-triphosphate (1.55 Å) reveal that it undergoes drastic conformational changes on ATP binding to attain a structure capable of dimerization. Mutations of the residues that stabilize the binding of ATP were defective in their ability to dimerize and do not inhibit ATP hydrolysis by FleQ. Conversely, the catalytic mutant of FleN, was an efficient inhibitor. These observations posit that the dimer is the functional form of FleN and it is nucleotide binding and not hydrolysis by FleN that is necessary to exert an antagonistic effect against FleQ. Our study shows that ATP-induced dimerization may be a strategy to achieve reversible inhibition of FleQ to fine-tune the function of this activator to an optimal level.
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Affiliation(s)
- Chanchal
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3(rd) Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India; Manipal University, Manipal, Karnataka, 576104, India
| | - Priyajit Banerjee
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3(rd) Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India
| | - Deepti Jain
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3(rd) Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India.
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