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Dhindwal P, Boniecki MT, Moore SA. Helicobacter pylori FlgN binds its substrate FlgK and the flagellum ATPase FliI in a similar manner observed for the FliT chaperone. Protein Sci 2024; 33:e4882. [PMID: 38151822 PMCID: PMC10804663 DOI: 10.1002/pro.4882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 12/19/2023] [Accepted: 12/20/2023] [Indexed: 12/29/2023]
Abstract
In bacterial flagellum biogenesis, secretion of the hook-filament junction proteins FlgK and FlgL and completion of the flagellum requires the FlgN chaperone. Similarly, the related FliT chaperone is necessary for the secretion of the filament cap protein FliD and binds the flagellar export gate protein FlhA and the flagellum ATPase FliI. FlgN and FliT require FliJ for effective substrate secretion. In Helicobacter pylori, neither FlgN, FliT, nor FliJ have been annotated. We demonstrate that the genome location of HP1120 is identical to that of flgN in other flagellated bacteria and that HP1120 is the homolog of Campylobacter jejuni FlgN. A modeled HP1120 structure contains three α-helices and resembles the FliT chaperone, sharing a similar substrate-binding pocket. Using pulldowns and thermophoresis, we show that both HP1120 and a HP1120Δ126-144 deletion mutant bind to FlgK with nanomolar affinity, but not to the filament cap protein FliD, confirming that HP1120 is FlgN. Based on size-exclusion chromatography and multi-angle light scattering, H. pylori FlgN binds to FlgK with 1:1 stoichiometry. Overall structural similarities between FlgN and FliT suggest that substrate recognition on FlgN primarily involves an antiparallel coiled-coil interface between the third helix of FlgN and the C-terminal helix of the substrate. A FlgNΔ126-144 N100A, Y103A, S111I triple mutant targeting this interface significantly impairs the binding of FlgK. Finally, we demonstrate that FlgNΔ126-144 , like FliT, binds with sub-micromolar affinity to the flagellum ATPase FliI or its N-terminal domain. Hence FlgN and FliT likely couple delivery of low-abundance export substrates to the flagellum ATPase FliI.
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Affiliation(s)
- Poonam Dhindwal
- Department of Biochemistry, Microbiology and ImmunologyCollege of Medicine, University of SaskatchewanSaskatoonCanada
| | - Michal T. Boniecki
- Department of Biochemistry, Microbiology and ImmunologyCollege of Medicine, University of SaskatchewanSaskatoonCanada
| | - Stanley A. Moore
- Department of Biochemistry, Microbiology and ImmunologyCollege of Medicine, University of SaskatchewanSaskatoonCanada
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Bai X, Chen X, Zhang D, Liu X, Li J. Targeted phytogenic compounds against Vibrio parahaemolyticus biofilms. Crit Rev Food Sci Nutr 2024:1-12. [PMID: 38189321 DOI: 10.1080/10408398.2023.2299949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
As one of main culprit of seafood-associated human illness, Vibrio parahaemolyticus can readily accumulate on biotic or abiotic surfaces to form biofilms in the seafood processing environment. Biofilm formation on various surfaces can provide a protective barrier for viable bacterial cells that are resistant to most traditional bacteriostatic measures. This underscores the necessity and urgency of developing effective alternative strategies to control V. parahaemolyticus biofilms. Plants have always provided an extensive and infinite source of biologically active compounds for "green" antibiofilm agents. This review summarizes recent developments in promising multitargeted phytogenic compounds against V. parahaemolyticus biofilms. This review provides valuable insights into potential research targets that can be pursued further to identify potent natural antibiofilm agents in the food industry.
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Affiliation(s)
- Xue Bai
- College of Food Science and Engineering, Bohai University, Jinzhou, China
| | - Xiaoli Chen
- College of Food Science and Engineering, Bohai University, Jinzhou, China
| | - Defu Zhang
- College of Food Science and Engineering, Bohai University, Jinzhou, China
| | - Xuefei Liu
- College of Food Science and Engineering, Bohai University, Jinzhou, China
| | - Jianrong Li
- College of Food Science and Engineering, Bohai University, Jinzhou, China
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Dong Y, Xu M, Wan X, Zhao D, Geng J, Huang H, Jiang M, Lu C, Liu Y. TonB systems are required for Aeromonas hydrophila motility by controlling the secretion of flagellin. Microbes Infect 2023; 25:105038. [PMID: 35963567 DOI: 10.1016/j.micinf.2022.105038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 08/03/2022] [Accepted: 08/03/2022] [Indexed: 02/04/2023]
Abstract
The TonB system is required for the active transport of iron compounds across the outer membrane in Gram-negative bacteria. Our previous data indicated that three TonB systems act coordinately to contribute to the motility of Aeromonas hydrophila NJ-35. In this study, we found that flagellum biogenesis was defective in the ΔtonB123 mutant. Subcellular localization indicated that the flagellin subunits FlaA and FlaB were trapped in the cytoplasm of ΔtonB123 mutant with reduced molecular mass. Overexpression of FlaA or FlaB in the ΔtonB123 mutant was unable to restore the secretion of flagellin subunits. Further investigation demonstrated that flagellins in the ΔtonB123 mutant showed a weak affinity for the flagellin-specific chaperone FliS, which is necessary for the export of flagellins. Deglycosylation analysis indicated that flagellins in the cytoplasm of the ΔtonB123 mutant were almost nonglycosylated. Our data suggested that disruption of tonB123 impairs the formation of flagella by inhibiting flagellin glycosylation and decreasing the binding affinity of flagellin for the chaperone FliS. Taken together, our findings indicate a new role of the TonB system in flagellar biogenesis in A. hydrophila.
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Affiliation(s)
- Yuhao Dong
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Meng Xu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Xihe Wan
- Institute of Oceanology and Marine Fisheries, Nantong, 226007, Jiangsu, China
| | - Dan Zhao
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Jinzhu Geng
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Hao Huang
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Mingguo Jiang
- Guangxi Key Laboratory for Polysaccharide Materials and Modifications, School of Marine Sciences and Biotechnology, Guangxi University for Nationalities, Nanning, 530008, Guangxi, China
| | - Chengping Lu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Yongjie Liu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China.
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Nedeljković M, Postel S, Pierce BG, Sundberg EJ. Molecular Determinants of Filament Capping Proteins Required for the Formation of Functional Flagella in Gram-Negative Bacteria. Biomolecules 2021; 11:biom11101397. [PMID: 34680030 PMCID: PMC8533109 DOI: 10.3390/biom11101397] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 09/17/2021] [Accepted: 09/20/2021] [Indexed: 11/28/2022] Open
Abstract
Bacterial flagella are cell surface protein appendages that are critical for motility and pathogenesis. Flagellar filaments are tubular structures constructed from thousands of copies of the protein flagellin, or FliC, arranged in helical fashion. Individual unfolded FliC subunits traverse the filament pore and are folded and sorted into place with the assistance of the flagellar capping protein complex, an oligomer of the FliD protein. The FliD filament cap is a stool-like structure, with its D2 and D3 domains forming a flat head region, and its D1 domain leg-like structures extending perpendicularly from the head towards the inner core of the filament. Here, using an approach combining bacterial genetics, motility assays, electron microscopy and molecular modeling, we define, in numerous Gram-negative bacteria, which regions of FliD are critical for interaction with FliC subunits and result in the formation of functional flagella. Our data indicate that the D1 domain of FliD is its sole functionally important domain, and that its flexible coiled coil region comprised of helices at its extreme N- and C-termini controls compatibility with the FliC filament. FliD sequences from different bacterial species in the head region are well tolerated. Additionally, head domains can be replaced by small peptides and larger head domains from different species and still produce functional flagella.
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Affiliation(s)
- Marko Nedeljković
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA;
| | - Sandra Postel
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Brian G. Pierce
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA;
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Eric J. Sundberg
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA;
- Correspondence:
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Al-Otaibi NS, Taylor AJ, Farrell DP, Tzokov SB, DiMaio F, Kelly DJ, Bergeron JRC. The cryo-EM structure of the bacterial flagellum cap complex suggests a molecular mechanism for filament elongation. Nat Commun 2020; 11:3210. [PMID: 32587243 PMCID: PMC7316729 DOI: 10.1038/s41467-020-16981-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 05/29/2020] [Indexed: 11/16/2022] Open
Abstract
The bacterial flagellum is a remarkable molecular motor, whose primary function in bacteria is to facilitate motility through the rotation of a filament protruding from the bacterial cell. A cap complex, consisting of an oligomer of the protein FliD, is localized at the tip of the flagellum, and is essential for filament assembly, as well as adherence to surfaces in some bacteria. However, the structure of the intact cap complex, and the molecular basis for its interaction with the filament, remains elusive. Here we report the cryo-EM structure of the Campylobacter jejuni cap complex, which reveals that FliD is pentameric, with the N-terminal region of the protomer forming an extensive set of contacts across several subunits, that contribute to FliD oligomerization. We also demonstrate that the native C. jejuni flagellum filament is 11-stranded, contrary to a previously published cryo-EM structure, and propose a molecular model for the filament-cap interaction. FliD forms a cap complex at the tip of bacterial flagella and is essential for flagellum filament assembly. Here, the authors present the cryo-EM structure of the Campylobacter jejuni cap complex, revealing a pentameric assembly of FliD and further show that the C. jejuni flagellum filament is 11-stranded.
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Affiliation(s)
- Natalie S Al-Otaibi
- Department of Molecular Biology and Biotechnology, the University of Sheffield, Sheffield, UK
| | - Aidan J Taylor
- Department of Molecular Biology and Biotechnology, the University of Sheffield, Sheffield, UK
| | - Daniel P Farrell
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Svetomir B Tzokov
- Department of Molecular Biology and Biotechnology, the University of Sheffield, Sheffield, UK
| | - Frank DiMaio
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - David J Kelly
- Department of Molecular Biology and Biotechnology, the University of Sheffield, Sheffield, UK.
| | - Julien R C Bergeron
- Department of Molecular Biology and Biotechnology, the University of Sheffield, Sheffield, UK. .,Randall Division of Cell and Molecular Biophysics, King's College London, London, UK.
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