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Chen Y, Tachiyama S, Li Y, Feng X, Zhao H, Wu Y, Guo Y, Lara-Tejero M, Hua C, Liu J, Gao B. Tetrameric PilZ protein stabilizes stator ring in complex flagellar motor and is required for motility in Campylobacter jejuni. Proc Natl Acad Sci U S A 2025; 122:e2412594121. [PMID: 39793078 PMCID: PMC11725899 DOI: 10.1073/pnas.2412594121] [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: 07/01/2024] [Accepted: 11/19/2024] [Indexed: 01/12/2025] Open
Abstract
Rotation of the bacterial flagellum, the first identified biological rotary machine, is driven by its stator units. Knowledge gained about the function of stator units has increasingly led to studies of rotary complexes in different cellular pathways. Here, we report that a tetrameric PilZ family protein, FlgX, is a structural component underneath the stator units in the flagellar motor of Campylobacter jejuni. FlgX forms a stable tetramer that does not bind cyclic di-GMP (c-di-GMP), unlike other canonical PilZ domain-containing proteins. Cryoelectron tomography and subtomogram averaging of flagellar motors in situ provide evidence that FlgX interacts with each stator unit and plays a critical role in stator ring assembly and stability. Furthermore, FlgX is conserved and was most likely present in the common ancestor of the phylum Campylobacterota. Overall, FlgX represents a divergence in function for PilZ superfamily proteins as well as a player in the key stator-rotor interaction of complex flagellar motors.
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Affiliation(s)
- Yuanyuan Chen
- Chinese Academy of Sciences Key Laboratory of Tropical Marine Bio Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, Guangdong Provincial Observation and Research Station for Coastal Upwelling Ecosystem, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou511458, China
- Sanya National Marine Ecosystem Research Station, Tropical Marine Biological Research Station in Hainan, Chinese Academy of Sciences, Sanya572000, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou511458, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Shoichi Tachiyama
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT06536
- Microbial Sciences Institute, Yale University, West Haven, CT06516
| | - Yuqian Li
- Chinese Academy of Sciences Key Laboratory of Tropical Marine Bio Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, Guangdong Provincial Observation and Research Station for Coastal Upwelling Ecosystem, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou511458, China
- Sanya National Marine Ecosystem Research Station, Tropical Marine Biological Research Station in Hainan, Chinese Academy of Sciences, Sanya572000, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou511458, China
| | - Xueyin Feng
- Chinese Academy of Sciences Key Laboratory of Tropical Marine Bio Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, Guangdong Provincial Observation and Research Station for Coastal Upwelling Ecosystem, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou511458, China
- Sanya National Marine Ecosystem Research Station, Tropical Marine Biological Research Station in Hainan, Chinese Academy of Sciences, Sanya572000, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou511458, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Hang Zhao
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT06536
- Microbial Sciences Institute, Yale University, West Haven, CT06516
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng475004, China
| | - Yanmin Wu
- Chinese Academy of Sciences Key Laboratory of Tropical Marine Bio Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, Guangdong Provincial Observation and Research Station for Coastal Upwelling Ecosystem, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou511458, China
- Sanya National Marine Ecosystem Research Station, Tropical Marine Biological Research Station in Hainan, Chinese Academy of Sciences, Sanya572000, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou511458, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Yu Guo
- Chinese Academy of Sciences Key Laboratory of Tropical Marine Bio Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, Guangdong Provincial Observation and Research Station for Coastal Upwelling Ecosystem, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou511458, China
- Sanya National Marine Ecosystem Research Station, Tropical Marine Biological Research Station in Hainan, Chinese Academy of Sciences, Sanya572000, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou511458, China
| | - María Lara-Tejero
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT06536
| | - Canfeng Hua
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT06536
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT06536
- Microbial Sciences Institute, Yale University, West Haven, CT06516
| | - Beile Gao
- Chinese Academy of Sciences Key Laboratory of Tropical Marine Bio Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, Guangdong Provincial Observation and Research Station for Coastal Upwelling Ecosystem, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou511458, China
- Sanya National Marine Ecosystem Research Station, Tropical Marine Biological Research Station in Hainan, Chinese Academy of Sciences, Sanya572000, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou511458, China
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Huang Z, Li Y, Yu K, Ma L, Pang B, Qin Q, Li J, Wang D, Gao H, Kan B. Genome-wide expanding of genetic evolution and potential pathogenicity in Vibrio alginolyticus. Emerg Microbes Infect 2024; 13:2350164. [PMID: 38687697 PMCID: PMC11132748 DOI: 10.1080/22221751.2024.2350164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 04/26/2024] [Indexed: 05/02/2024]
Abstract
Vibrio alginolyticus, an emergent species of Vibrio genus, exists in aquatic and marine environments. It has undergone genetic diversification, but its detailed genomic diversity is still unclear. Here, we performed a multi-dimensional comparative genomic analysis to explore the population phylogeny, virulence-related genes and potential drug resistance genes of 184 V. alginolyticus isolates. Although genetic diversity is complex, we analysed the population structure using three sub-datasets, including the subdivision for three lineages into sublineages and the distribution of strains in the marine ecological niche. Accessory genes, most of which reclassified V. alginolyticus genomes as different but with relatively close affinities, were nonuniformly distributed among these isolates. We demonstrated that the spread of some post-evolutionary isolates (mainly L3 strains isolated from Chinese territorial seas) was likely to be closely related to human activities, whereas other more ancestral strains (strains in the L1 and L2) tended to be locally endemic and formed clonal complex groups. In terms of pathogenicity, the potential virulence factors were mainly associated with toxin, adherence, motility, chemotaxis, and the type III secretion system (T3SS). We also found five types of antibacterial drug resistance genes. The prevalence of β-lactam resistance genes was 100%, which indicated that there may be a potential risk of natural resistance to β-lactam drugs. Our study reveals insights into genomic characteristics, evolution and potential virulence-associated gene profiles of V. alginolyticus.
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Affiliation(s)
- Zhenzhou Huang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
- Hangzhou Center for Disease Control and Prevention, Zhejiang, People’s Republic of China
| | - Yanjun Li
- The Sixth Medical Center of PLA General Hospital, Beijing, People’s Republic of China
| | - Keyi Yu
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Lizhi Ma
- The Third Medical Center, Chinese PLA (People’s Liberation Army) General Hospital, Beijing, People’s Republic of China
| | - Bo Pang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Qin Qin
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Jie Li
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Duochun Wang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - He Gao
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Biao Kan
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
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Fu S, Tian M, Chen M, Wu Z, Zhang R, Yuan J. MotY modulates proton-driven flagellar motor output in Pseudomonas aeruginosa. BMC Microbiol 2024; 24:461. [PMID: 39516722 PMCID: PMC11546298 DOI: 10.1186/s12866-024-03602-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2024] [Accepted: 10/23/2024] [Indexed: 11/16/2024] Open
Abstract
MotY homologs are present in a variety of monotrichous bacterial strains and are thought to form an additional structural T ring in flagellar motors. While MotY potentially plays an important role in motor torque generation, its impact on motor output dynamics remains poorly understood. In this study, we investigate the role of MotY in P. aeruginosa, elucidating its interactions with the two sets of stator units (MotAB and MotCD) using Förster resonance energy transfer (FRET) assays. Employing a newly developed bead assay, we characterize the dynamic behavior of flagellar motors in motY mutants, identifying MotY as the key functional protein to affect the clockwise bias of naturally unbiased motors in P. aeruginosa. Our findings reveal that MotY enhances stator assembly efficiency without affecting the overall assembly of the flagellar structure. Additionally, we demonstrate that MotY is essential for maintaining motor torque and regulating switching rates. Our study highlights the physiological significance of MotY in fine-tuning flagellar motor function in complex environments.
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Affiliation(s)
- Sanyuan Fu
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Maojin Tian
- Center of Translational Medicine, Zibo Central Hospital Affiliated to Binzhou Medical University, Zibo, Shandong, 255036, China
| | - Min Chen
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Zhengyu Wu
- Research Center of Translational Medicine, Central Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, 250013, China.
| | - Rongjing Zhang
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
| | - Junhua Yuan
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
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4
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Bodra N, Toh E, Nadeem A, Wai SN, Persson K. MakC and MakD are two proteins associated with a tripartite toxin of Vibrio cholerae. Front Microbiol 2024; 15:1457850. [PMID: 39421563 PMCID: PMC11484084 DOI: 10.3389/fmicb.2024.1457850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2024] [Accepted: 09/11/2024] [Indexed: 10/19/2024] Open
Abstract
Pathogenic serotypes of Vibrio cholerae, transmitted through contaminated water and food, are responsible for outbreaks of cholera, an acute diarrheal disease. While the cholera toxin is the primary virulence factor, V. cholerae also expresses other virulence factors, such as the tripartite toxin MakABE that is secreted via the bacterial flagellum. These three proteins are co-expressed with two accessory proteins, MakC and MakD, whose functions remain unknown. Here, we present the crystal structures of MakC and MakD, revealing that they are similar in both sequence and structure but lack other close structural relatives. Our study further investigates the roles of MakC and MakD, focusing on their impact on the expression and secretion of the components of the MakABE tripartite toxin. Through deletion mutant analysis, we found that individual deletions of makC or makD do not significantly affect MakA expression or secretion. However, the deletion of both makC and makD impairs the expression of MakB, which is directly downstream, and decreases the expression of MakE, which is separated from makCD by two genes. Conversely, MakA, encoded by the makA gene located between makB and makE, is expressed normally but its secretion is impaired. Additionally, our findings indicate that MakC, in contrast to MakD, exhibits strong interactions with other proteins. Furthermore, both MakC and MakD were observed to be localized within the cytosol of the bacterial cell. This study provides new insights into the regulatory mechanisms affecting the Mak protein family in V. cholerae and highlights the complex interplay between gene proximity and protein expression.
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Affiliation(s)
- Nandita Bodra
- Department of Chemistry, Umeå University, Umeå, Sweden
- Umeå Center for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Eric Toh
- Umeå Center for Microbial Research (UCMR), Umeå University, Umeå, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Aftab Nadeem
- Umeå Center for Microbial Research (UCMR), Umeå University, Umeå, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Sun Nyunt Wai
- Umeå Center for Microbial Research (UCMR), Umeå University, Umeå, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Karina Persson
- Department of Chemistry, Umeå University, Umeå, Sweden
- Umeå Center for Microbial Research (UCMR), Umeå University, Umeå, Sweden
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5
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Gambino M, Sørensen MCH. Flagellotropic phages: common yet diverse host interaction strategies. Curr Opin Microbiol 2024; 78:102451. [PMID: 38452595 DOI: 10.1016/j.mib.2024.102451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 01/14/2024] [Accepted: 02/10/2024] [Indexed: 03/09/2024]
Abstract
Many bacteriophages (phages) interact with flagella and rely on bacterial motility for successful infection of their hosts. Yet, limited information is available on how phages have evolved to recognize and bind both flagella and subsequent surface receptors for phage DNA injection. Here, we present an update on the current knowledge of flagellotropic phages using a few well-studied phages as examples to unravel the molecular details of bacterial host recognition. We discuss the recent advances in the role of globular exposed flagellin domains and flagella glycosylation in phage binding to the flagella. In addition, we present diverse types of surface receptors and phage components responsible for the interaction with the host. Finally, we point to questions remaining to be answered and new approaches to study this unique group of phages.
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Affiliation(s)
- Michela Gambino
- Institute of Conservation, Royal Danish Academy, Copenhagen, Denmark
| | - Martine C H Sørensen
- Section of Food Safety and Zoonoses, Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark.
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Vélez-González F, Marcos-Vilchis A, Vega-Baray B, Dreyfus G, Poggio S, Camarena L. Rotation of the Fla2 flagella of Cereibacter sphaeroides requires the periplasmic proteins MotK and MotE that interact with the flagellar stator protein MotB2. PLoS One 2024; 19:e0298028. [PMID: 38507361 PMCID: PMC10954123 DOI: 10.1371/journal.pone.0298028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 01/16/2024] [Indexed: 03/22/2024] Open
Abstract
The bacterial flagellum is a complex structure formed by more than 25 different proteins, this appendage comprises three conserved structures: the basal body, the hook and filament. The basal body, embedded in the cell envelope, is the most complex structure and houses the export apparatus and the motor. In situ images of the flagellar motor in different species have revealed a huge diversity of structures that surround the well-conserved periplasmic components of the basal body. The identity of the proteins that form these novel structures in many cases has been elucidated genetically and biochemically, but in others they remain to be identified or characterized. In this work, we report that in the alpha proteobacteria Cereibacter sphaeroides the novel protein MotK along with MotE are essential for flagellar rotation. We show evidence that these periplasmic proteins interact with each other and with MotB2. Moreover, these proteins localize to the flagellated pole and MotK localization is dependent on MotB2 and MotA2. These results together suggest that the role of MotK and MotE is to activate or recruit the flagellar stators to the flagellar structure.
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Affiliation(s)
- Fernanda Vélez-González
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Arely Marcos-Vilchis
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Benjamín Vega-Baray
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Georges Dreyfus
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Sebastian Poggio
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Laura Camarena
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Ribardo DA, Johnson JJ, Hendrixson DR. Viscosity-dependent determinants of Campylobacter jejuni impacting the velocity of flagellar motility. mBio 2024; 15:e0254423. [PMID: 38085029 PMCID: PMC10790790 DOI: 10.1128/mbio.02544-23] [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: 09/28/2023] [Accepted: 11/06/2023] [Indexed: 01/17/2024] Open
Abstract
IMPORTANCE Bacteria can adapt flagellar motor output in response to the load that the extracellular milieu imparts on the flagellar filament to enable propulsion. Bacteria can adapt flagellar motor output in response to the load that the extracellular milieu imparts on the flagellar filament to enable propulsion through diverse environments. These changes may involve increasing power and torque in high-viscosity environments or reducing power and flagellar rotation upon contact with a surface. C. jejuni swimming velocity in low-viscosity environments is comparable to other bacterial flagellates and increases significantly as external viscosity increases. In this work, we provide evidence that the mechanics of the C. jejuni flagellar motor has evolved to naturally promote high swimming velocity in high-viscosity environments. We found that C. jejuni produces VidA and VidB as auxiliary proteins to specifically affect flagellar motor activity in low viscosity to reduce swimming velocity. Our findings provide some of the first insights into different mechanisms that exist in bacteria to alter the mechanics of a flagellar motor, depending on the viscosity of extracellular environments.
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Affiliation(s)
- Deborah A. Ribardo
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jeremiah J. Johnson
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - David R. Hendrixson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Johnson MD, Sakai HD, Paul B, Nunoura T, Dalvi S, Mudaliyar M, Shepherd DC, Shimizu M, Udupa S, Ohkuma M, Kurosawa N, Ghosal D. Large attachment organelle mediates interaction between Nanobdellota archaeon YN1 and its host. THE ISME JOURNAL 2024; 18:wrae154. [PMID: 39113594 PMCID: PMC11420986 DOI: 10.1093/ismejo/wrae154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 06/25/2024] [Accepted: 08/07/2024] [Indexed: 09/25/2024]
Abstract
DPANN archaea are an enigmatic superphylum that are difficult to isolate and culture in the laboratory due to their specific culture conditions and apparent ectosymbiotic lifestyle. Here, we successfully isolated and cultivated a coculture system of a novel Nanobdellota archaeon YN1 and its host Sulfurisphaera ohwakuensis YN1HA. We characterized the coculture system by complementary methods, including metagenomics and metabolic pathway analysis, fluorescence microscopy, and high-resolution electron cryo-tomography (cryoET). We show that YN1 is deficient in essential metabolic processes and requires host resources to proliferate. CryoET imaging revealed an enormous attachment organelle present in the YN1 envelope that forms a direct interaction with the host cytoplasm, bridging the two cells. Together, our results unravel the molecular and structural basis of ectosymbiotic relationship between YN1 and YN1HA. This research broadens our understanding of DPANN biology and the versatile nature of their ectosymbiotic relationships.
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Affiliation(s)
- Matthew D Johnson
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Hiroyuki D Sakai
- Department of Science and Engineering for Sustainable Innovation, Faculty of Science and Engineering, Soka University, Hachioji, Tokyo 192-8577, Japan
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Bindusmita Paul
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Takuro Nunoura
- Research Center for Bioscience and Nanoscience (CeBN), Japan Agency for Marine-Earth Science & Technology (JAMSTEC), Yokosuka 237-0061, Japan
| | - Somavally Dalvi
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Manasi Mudaliyar
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Doulin C Shepherd
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Michiru Shimizu
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Shubha Udupa
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Moriya Ohkuma
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Norio Kurosawa
- Department of Science and Engineering for Sustainable Innovation, Faculty of Science and Engineering, Soka University, Hachioji, Tokyo 192-8577, Japan
| | - Debnath Ghosal
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
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9
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Zhang J, Liu K, Gong X, Zhang N, Zeng Y, Ren W, Huang A, Long H, Xie Z. Transcriptome analysis of the hepatopancreas from the Litopenaeus vannamei infected with different flagellum types of Vibrio alginolyticus strains. Front Cell Infect Microbiol 2023; 13:1265917. [PMID: 38076457 PMCID: PMC10703188 DOI: 10.3389/fcimb.2023.1265917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 11/06/2023] [Indexed: 12/18/2023] Open
Abstract
Vibrio alginolyticus, one of the prevalently harmful Vibrio species found in the ocean, causes significant economic damage in the shrimp farming industry. Its flagellum serves as a crucial virulence factor in the invasion of host organisms. However, the processes of bacteria flagella recognition and activation of the downstream immune system in shrimp remain unclear. To enhance comprehension of this, a ΔflhG strain was created by in-frame deletion of the flhG gene in V. alginolyticus strain HN08155. Then we utilized the transcriptome analysis to examine the different immune responses in Litopenaeus vannamei hepatopancreas after being infected with the wild type and the mutant strains. The results showed that the ΔflhG strain, unlike the wild type, lost its ability to regulate flagella numbers negatively and displayed multiple flagella. When infected with the hyperflagella-type strain, the RNA-seq revealed the upregulation of several immune-related genes in the shrimp hepatopancreas. Notably, two C-type lectins (CTLs), namely galactose-specific lectin nattectin and macrophage mannose receptor 1, and the TNF receptor-associated factor (TRAF) 6 gene were upregulated significantly. These findings suggested that C-type lectins were potentially involved in flagella recognition in shrimp and the immune system was activated through the TRAF6 pathway after flagella detection by CTLs.
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Affiliation(s)
- Jingwen Zhang
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, China
- Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China
| | - Kaifang Liu
- School of Fisheries, Xinyang Agriculture and Forestry University, Xinyang, China
| | - Xiaoxiao Gong
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, China
- Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China
| | - Na Zhang
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, China
- Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China
| | - Yanhua Zeng
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, China
- Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China
- Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, China
| | - Wei Ren
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, China
- Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China
- Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, China
| | - Aiyou Huang
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, China
- Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China
- Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, China
| | - Hao Long
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, China
- Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China
- Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, China
| | - Zhenyu Xie
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, China
- Laboratory of Development and Utilization of Marine Microbial Resource, Hainan University, Haikou, China
- Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, China
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10
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Nandel V, Scadden J, Baker MAB. Ion-Powered Rotary Motors: Where Did They Come from and Where They Are Going? Int J Mol Sci 2023; 24:10601. [PMID: 37445779 PMCID: PMC10341847 DOI: 10.3390/ijms241310601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
Molecular motors are found in many living organisms. One such molecular machine, the ion-powered rotary motor (IRM), requires the movement of ions across a membrane against a concentration gradient to drive rotational movement. The bacterial flagellar motor (BFM) is an example of an IRM which relies on ion movement through the stator proteins to generate the rotation of the flagella. There are many ions which can be used by the BFM stators to power motility and different ions can be used by a single bacterium expressing multiple stator variants. The use of ancestral sequence reconstruction (ASR) and functional analysis of reconstructed stators shows promise for understanding how these proteins evolved and when the divergence in ion use may have occurred. In this review, we discuss extant BFM stators and the ions that power them as well as recent examples of the use of ASR to study ion-channel selectivity and how this might be applied to further study of the BFM stator complex.
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Affiliation(s)
| | | | - Matthew A. B. Baker
- School of Biotechnology and Biomolecular Sciences (BABS), University of New South Wales, Sydney, NSW 2033, Australia; (V.N.); (J.S.)
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11
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Da F, Wan X, Lin G, Jian J, Cai S. Characterization of fliR-deletion mutant Δ fliR from Vibrio alginolyticus and the evaluation as a live attenuated vaccine. Front Cell Infect Microbiol 2023; 13:1162299. [PMID: 37180437 PMCID: PMC10166871 DOI: 10.3389/fcimb.2023.1162299] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 04/05/2023] [Indexed: 05/16/2023] Open
Abstract
Vibrio alginolyticus is the common pathogen affecting various species of marine organisms. It has been demonstrated that fliR is a necessary virulence factor to adhere and infect their hosts for pathogenic bacteria. Frequent disease outbreaks in aquaculture have highlighted the necessity of developing effective vaccines. In the present study, in order to investigate the function of fliR in V.alginolyticus, the fliR deletion mutant ΔfliR was constructed and its biological properties were evaluated, additionally, the differences in gene expression levels between wild-type and ΔfliR were analyzed by transcriptomics. Finally, ΔfliR was used as a live attenuated vaccine to immunize grouper via the intraperitoneal route to evaluate its protective effect. Results show that fliR gene of V. alginolyticus was identified as being 783 bp in length, encoding 260 amino acids, and showing significant similarity to homologs of other Vibrio species. The fliR-deletion mutant ΔfliR of V. alginolyticus was successfully constructed, and its biological phenotype analysis showed no significant differences in growth capacity and extracellular enzyme activity compared to the wild-type. However, a substantial reduction of motility ability was detected in ΔfliR. Transcriptomic analysis revealed that the absence of fliR gene is responsible for a significantly decreased expression of flagellar genes, including flaA, flaB, fliS, flhB and fliM. The fliR-deletion mainly affects the related pathways involved in cell motility, membrane transport, signal transduction, carbohydrate metabolism, and amino acid metabolism in V. alginolyticus. The efficacy of ΔfliR as a candidate of live attenuated vaccine were evaluated by intraperitoneal injection in grouper. The ΔfliR provided the RPS (Relative protection rate) of 67.2% against V. alginolyticus in groupers. The ΔfliR efficiently stimulated antibody production with specific IgM still detected at 42 d post-vaccination, and significantly elevated the activity of antioxidant enzymes like Catalase (CAT), Superoxide dismutase (SOD), and lactate dehydrogenase (LDH) in the serum. The higher expression levels of immune-related genes were observed in the immune tissues of inoculated grouper compared to the control. In conclusion, ΔfliR effectively improved the immunity of inoculated fish. The results suggest that ΔfliR is an effective live attenuated vaccine against vibriosis in in grouper.
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Affiliation(s)
| | | | | | | | - Shuanghu Cai
- Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Shenzhen Institute of Guangdong Ocean University, Fisheries College of Guangdong Ocean University, Guangdong, China
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12
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Tao A, Liu G, Zhang R, Yuan J. Precise Measurement of the Stoichiometry of the Adaptive Bacterial Flagellar Switch. mBio 2023; 14:e0018923. [PMID: 36946730 PMCID: PMC10128058 DOI: 10.1128/mbio.00189-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023] Open
Abstract
The cytoplasmic ring (C-ring) of the bacterial flagellar motor controls the motor rotation direction, thereby controlling bacterial run-and-tumble behavior. The C-ring has been shown to undergo adaptive remodeling in response to changes in motor directional bias. However, the stoichiometry and arrangement of the C-ring is still unclear due to contradiction between the results from fluorescence studies and cryo-electron microscopy (cryo-EM) structural analysis. Here, by using the copy number of FliG molecules (34) in the C-ring as a reference, we precisely measured the copy numbers of FliM molecules in motors rotating exclusively counterclockwise (CCW) and clockwise (CW). We surprisingly found that there are on average 45 and 58 FliM molecules in CW and CCW rotating motors, respectively, which are much higher than previous estimates. Our results suggested a new mechanism of C-ring adaptation, that is, extra FliM molecules could be bound to the primary C-ring with probability depending on the motor rotational direction. We further confirmed that all of the FliM molecules in the C-ring function in chemotaxis signaling transduction because all of them could be bound by the chemotactic response regulator CheY-P. Our measurements provided new insights into the structure and arrangement of the flagellar switch. IMPORTANCE The bacterial flagellar switch can undergo adaptive remodeling in response to changes in motor rotation direction, thereby shifting its operating point to match the output of the chemotaxis signaling pathway. However, it remains unclear how the flagellar switch accomplishes this adaptive remodeling. Here, via precise fluorescence studies, we measured the absolute copy numbers of the critical component in the switch for motors rotating counterclockwise and clockwise, obtaining much larger numbers than previous relative estimates. Our results suggested a new mechanism of adaptive remodeling of the flagellar switch and provided new insights for updating the conformation spread model of the switch.
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Affiliation(s)
- Antai Tao
- Department of Physics, University of Science and Technology of China, Hefei, Anhui, China
| | - Guangzhe Liu
- Wenzhou Institute, University of Chinese Academy of Science, Wenzhou, Zhejiang, P.R. China
- School of Engineering and Science, University of Chinese Academy of Science, Beijing, P.R. China
| | - Rongjing Zhang
- Department of Physics, University of Science and Technology of China, Hefei, Anhui, China
| | - Junhua Yuan
- Department of Physics, University of Science and Technology of China, Hefei, Anhui, China
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13
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Lloyd CJ, Klose KE. The Vibrio Polar Flagellum: Structure and Regulation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1404:77-97. [PMID: 36792872 DOI: 10.1007/978-3-031-22997-8_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Here we discuss the structure and regulation of the Vibrio flagellum and its role in the virulence of pathogenic species. We will cover some of the novel insights into the structure of this nanomachine that have recently been enabled by cryoelectron tomography. We will also highlight the recent genetic studies that have increased our understanding in flagellar synthesis specifically at the bacterial cell pole, temporal regulation of flagellar genes, and how the flagellum enables directional motility through Run-Reverse-Flick cycles.
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Affiliation(s)
- Cameron J Lloyd
- South Texas Center for Emerging Infectious Diseases, University of Texas San Antonio, San Antonio, TX, USA.,Department of Molecular Microbiology and Immunology, University of Texas San Antonio, San Antonio, TX, USA
| | - Karl E Klose
- South Texas Center for Emerging Infectious Diseases, University of Texas San Antonio, San Antonio, TX, USA. .,Department of Molecular Microbiology and Immunology, University of Texas San Antonio, San Antonio, TX, USA.
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14
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Lai L, Cheung YW, Martinez M, Kixmoeller K, Palao L, Steimle S, Ho MC, Black BE, Lai EM, Chang YW. In Situ Structure Determination of Bacterial Surface Nanomachines Using Cryo-Electron Tomography. Methods Mol Biol 2023; 2646:211-248. [PMID: 36842118 DOI: 10.1007/978-1-0716-3060-0_18] [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] [Indexed: 04/13/2023]
Abstract
Bacterial surface nanomachines are often refractory to structural determination in their intact form due to their extensive association with the cell envelope preventing them from being properly purified for traditional structural biology methods. Cryo-electron tomography (cryo-ET) is an emerging branch of cryo-electron microscopy that can visualize supramolecular complexes directly inside frozen-hydrated cells in 3D at nanometer resolution, therefore posing a unique capability to study the intact structures of bacterial surface nanomachines in situ and reveal their molecular association with other cellular components. Furthermore, the resolution of cryo-ET is continually improving alongside methodological advancement. Here, using the type IV pilus machine in Myxococcus xanthus as an example, we describe a step-by-step workflow for in situ structure determination including sample preparation and screening, microscope and camera tuning, tilt series acquisition, data processing and tomogram reconstruction, subtomogram averaging, and structural analysis.
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Affiliation(s)
- Longsheng Lai
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yee-Wai Cheung
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Matthew Martinez
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kathryn Kixmoeller
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Leon Palao
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Stefan Steimle
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Meng-Chiao Ho
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Ben E Black
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Erh-Min Lai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yi-Wei Chang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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15
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Nishikino T, Takekawa N, Tran DP, Kishikawa JI, Hirose M, Onoe S, Kojima S, Homma M, Kitao A, Kato T, Imada K. Structure of MotA, a flagellar stator protein, from hyperthermophile. Biochem Biophys Res Commun 2022; 631:78-85. [PMID: 36179499 DOI: 10.1016/j.bbrc.2022.09.072] [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: 09/11/2022] [Revised: 09/13/2022] [Accepted: 09/18/2022] [Indexed: 11/02/2022]
Abstract
Many motile bacteria swim and swarm toward favorable environments using the flagellum, which is rotated by a motor embedded in the inner membrane. The motor is composed of the rotor and the stator, and the motor torque is generated by the change of the interaction between the rotor and the stator induced by the ion flow through the stator. A stator unit consists of two types of membrane proteins termed A and B. Recent cryo-EM studies on the stators from mesophiles revealed that the stator consists of five A and two B subunits, whereas the low-resolution EM analysis showed that purified hyperthermophilic MotA forms a tetramer. To clarify the assembly formation and factors enhancing thermostability of the hyperthermophilic stator, we determined the cryo-EM structure of MotA from Aquifex aeolicus (Aa-MotA), a hyperthermophilic bacterium, at 3.42 Å resolution. Aa-MotA forms a pentamer with pseudo C5 symmetry. A simulated model of the Aa-MotA5MotB2 stator complex resembles the structures of mesophilic stator complexes, suggesting that Aa-MotA can assemble into a pentamer equivalent to the stator complex without MotB. The distribution of hydrophobic residues of MotA pentamers suggests that the extremely hydrophobic nature in the subunit boundary and the transmembrane region is a key factor to stabilize hyperthermophilic Aa-MotA.
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Affiliation(s)
- Tatsuro Nishikino
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Norihiro Takekawa
- Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka, 560-0043, Japan
| | - Duy Phuoc Tran
- School of Life Sciences and Technology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - Jun-Ichi Kishikawa
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Mika Hirose
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Sakura Onoe
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan
| | - Akio Kitao
- School of Life Sciences and Technology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - Takayuki Kato
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Katsumi Imada
- Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka, 560-0043, Japan.
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16
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Abstract
Swimming bacterial pathogens can penetrate and shape the membranes of their host cells. We study an artificial model system of this kind comprising Escherichia coli enclosed inside vesicles, which consist of nothing more than a spherical membrane bag. The bacteria push out membrane tubes, and the tubes propel the vesicles. This phenomenon is intriguing because motion cannot be generated by pushing the vesicles from within. We explain the motility of our artificial cell by a shape coupling between the flagella of each bacterium and the enclosing membrane tube. This constitutes a design principle for conferring motility to cell-sized vesicles and demonstrates the universality of lipid membranes as a building block in the development of new biohybrid systems. We study a synthetic system of motile Escherichia coli bacteria encapsulated inside giant lipid vesicles. Forces exerted by the bacteria on the inner side of the membrane are sufficient to extrude membrane tubes filled with one or several bacteria. We show that a physical coupling between the membrane tube and the flagella of the enclosed cells transforms the tube into an effective helical flagellum propelling the vesicle. We develop a simple theoretical model to estimate the propulsive force from the speed of the vesicles and demonstrate the good efficiency of this coupling mechanism. Together, these results point to design principles for conferring motility to synthetic cells.
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17
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Flagellotropic Bacteriophages: Opportunities and Challenges for Antimicrobial Applications. Int J Mol Sci 2022; 23:ijms23137084. [PMID: 35806089 PMCID: PMC9266447 DOI: 10.3390/ijms23137084] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/18/2022] [Accepted: 06/21/2022] [Indexed: 12/22/2022] Open
Abstract
Bacteriophages (phages) are the most abundant biological entities in the biosphere. As viruses that solely infect bacteria, phages have myriad healthcare and agricultural applications including phage therapy and antibacterial treatments in the foodservice industry. Phage therapy has been explored since the turn of the twentieth century but was no longer prioritized following the invention of antibiotics. As we approach a post-antibiotic society, phage therapy research has experienced a significant resurgence for the use of phages against antibiotic-resistant bacteria, a growing concern in modern medicine. Phages are extraordinarily diverse, as are their host receptor targets. Flagellotropic (flagellum-dependent) phages begin their infection cycle by attaching to the flagellum of their motile host, although the later stages of the infection process of most of these phages remain elusive. Flagella are helical appendages required for swimming and swarming motility and are also of great importance for virulence in many pathogenic bacteria of clinical relevance. Not only is bacterial motility itself frequently important for virulence, as it allows pathogenic bacteria to move toward their host and find nutrients more effectively, but flagella can also serve additional functions including mediating bacterial adhesion to surfaces. Flagella are also a potent antigen recognized by the human immune system. Phages utilizing the flagellum for infections are of particular interest due to the unique evolutionary tradeoff they force upon their hosts: by downregulating or abolishing motility to escape infection by a flagellotropic phage, a pathogenic bacterium would also likely attenuate its virulence. This factor may lead to flagellotropic phages becoming especially potent antibacterial agents. This review outlines past, present, and future research of flagellotropic phages, including their molecular mechanisms of infection and potential future applications.
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18
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Rieu M, Krutyholowa R, Taylor NMI, Berry RM. A new class of biological ion-driven rotary molecular motors with 5:2 symmetry. Front Microbiol 2022; 13:948383. [PMID: 35992645 PMCID: PMC9389320 DOI: 10.3389/fmicb.2022.948383] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 07/04/2022] [Indexed: 11/15/2022] Open
Abstract
Several new structures of three types of protein complexes, obtained by cryo-electron microscopy (cryo-EM) and published between 2019 and 2021, identify a new family of natural molecular wheels, the "5:2 rotary motors." These span the cytoplasmic membranes of bacteria, and their rotation is driven by ion flow into the cell. They consist of a pentameric wheel encircling a dimeric axle within the cytoplasmic membrane of both Gram-positive and gram-negative bacteria. The axles extend into the periplasm, and the wheels extend into the cytoplasm. Rotation of these wheels has never been observed directly; it is inferred from the symmetry of the complexes and from the roles they play within the larger systems that they are known to power. In particular, the new structure of the stator complex of the Bacterial Flagellar Motor, MotA5B2, is consistent with a "wheels within wheels" model of the motor. Other 5:2 rotary motors are believed to share the core rotary function and mechanism, driven by ion-motive force at the cytoplasmic membrane. Their structures diverge in their periplasmic and cytoplasmic parts, reflecting the variety of roles that they perform. This review focuses on the structures of 5:2 rotary motors and their proposed mechanisms and functions. We also discuss molecular rotation in general and its relation to the rotational symmetry of molecular complexes.
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Affiliation(s)
- Martin Rieu
- Department of Physics, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building University of Oxford, Oxford, United Kingdom
| | - Roscislaw Krutyholowa
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Nicholas M. I. Taylor
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
- Nicholas M. I. Taylor,
| | - Richard M. Berry
- Department of Physics, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building University of Oxford, Oxford, United Kingdom
- *Correspondence: Richard M. Berry,
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19
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Abstract
The bacterial flagellum is a large macromolecular assembly that acts as propeller, providing motility through the rotation of a long extracellular filament. It is composed of over 20 different proteins, many of them highly oligomeric. Accordingly, it has attracted a huge amount of interest amongst researchers and the wider public alike. Nonetheless, most of its molecular details had long remained elusive.This however has changed recently, with the emergence of cryo-EM to determine the structure of protein assemblies at near-atomic resolution. Within a few years, the atomic details of most of the flagellar components have been elucidated, revealing not only its overall architecture but also the molecular details of its rotation mechanism. However, many questions remained unaddressed, notably on the complexity of the assembly of such an intricate machinery.In this chapter, we review the current state of our understanding of the bacterial flagellum structure, focusing on the recent development from cryo-EM. We also highlight the various elements that still remain to be fully characterized. Finally, we summarize the existing model for flagellum assembly and discuss some of the outstanding questions that are still pending in our understanding of the diversity of assembly pathways.
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Affiliation(s)
- Natalie S Al-Otaibi
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Julien R C Bergeron
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK.
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20
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Homma M, Nishikino T, Kojima S. Achievements in bacterial flagellar research with focus on Vibrio species. Microbiol Immunol 2021; 66:75-95. [PMID: 34842307 DOI: 10.1111/1348-0421.12954] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/24/2021] [Accepted: 11/25/2021] [Indexed: 12/01/2022]
Abstract
In 1980's, the most genes involved in the bacterial flagellar function and formation had been isolated though many of their functions or roles were not clarified. Bacterial flagella are the primary locomotive organ and are not necessary for growing in vitro but are probably essential for living in natural condition and are involved in the pathogenicity. In vitro, the flagella-deficient strains can grow at rates similar to wild-type strains. More than 50 genes are responsible for flagellar function, and the flagellum is constructed by more than 20 structural proteins. The maintenance cost of flagellum is high as several genes are required for its development. The fact that it evolved as a motor organ even with such the high cost shows that the motility is indispensable to survive under the harsh environment of Earth. In this review, we focus on flagella-related research conducted by the authors for about 40 years and flagellar research focused on Vibrio spp. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University
| | | | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University
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21
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Lack of N-Terminal Segment of the Flagellin Protein Results in the Production of a Shortened Polar Flagellum in the Deep-Sea Sedimentary Bacterium Pseudoalteromonas sp. Strain SM9913. Appl Environ Microbiol 2021; 87:e0152721. [PMID: 34406825 DOI: 10.1128/aem.01527-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial polar flagella, comprised of flagellin, are essential for bacterial motility. Pseudoalteromonas sp. strain SM9913 is a bacterium isolated from deep-sea sediments. Unlike other Pseudoalteromonas strains that have a long polar flagellum, strain SM9913 has an abnormally short polar flagellum. Here, we investigated the underlying reason for the short flagellum and found that a single-base mutation was responsible for the altered flagellar assembly. This mutation leads to the fragmentation of the flagellin gene into two genes, PSM_A2281, encoding the core segment and the C-terminal segment, and PSM_A2282, encoding the N-terminal segment, and only gene PSM_A2281 is involved in the production of the short polar flagellum. When a chimeric gene of PSM_A2281 and PSM_A2282 encoding an intact flagellin, A2281::82, was expressed, a long polar flagellum was produced, indicating that the N-terminal segment of flagellin contributes to the production of a polar flagellum of a normal length. Analyses of the simulated structures of A2281 and A2281::82 and that of the flagellar filament assembled with A2281::82 indicate that due to the lack of two α-helices, the core of the flagellar filament assembled with A2281 is incomplete and is likely too weak to support the stability and movement of a long flagellum. This mutation in strain SM9913 had little effect on its growth and only a small effect on its swimming motility, implying that strain SM9913 can live well with this mutation in natural sedimentary environments. This study provides a better understanding of the assembly and production of bacterial flagella. IMPORTANCE Polar flagella, which are essential organelles for bacterial motility, are comprised of multiple flagellin subunits. A flagellin molecule contains an N-terminal segment, a core segment, and a C-terminal segment. The results of this investigation of the deep-sea sedimentary bacterium Pseudoalteromonas sp. strain SM9913 demonstrate that a single-base mutation in the flagellin gene leads to the production of an incomplete flagellin without the N-terminal segment and that the loss of the N-terminal segment of the flagellin protein results in the production of a shortened polar flagellar filament. Our results shed light on the important function of the N-terminal segment of flagellin in the assembly and stability of bacterial flagellar filament.
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22
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Hu H, Santiveri M, Wadhwa N, Berg HC, Erhardt M, Taylor NMI. Structural basis of torque generation in the bi-directional bacterial flagellar motor. Trends Biochem Sci 2021; 47:160-172. [PMID: 34294545 DOI: 10.1016/j.tibs.2021.06.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 06/16/2021] [Accepted: 06/18/2021] [Indexed: 12/11/2022]
Abstract
The flagellar stator unit is an oligomeric complex of two membrane proteins (MotA5B2) that powers bi-directional rotation of the bacterial flagellum. Harnessing the ion motive force across the cytoplasmic membrane, the stator unit operates as a miniature rotary motor itself to provide torque for rotation of the flagellum. Recent cryo-electron microscopic (cryo-EM) structures of the stator unit provided novel insights into its assembly, function, and subunit stoichiometry, revealing the ion flux pathway and the torque generation mechanism. Furthermore, in situ cryo-electron tomography (cryo-ET) studies revealed unprecedented details of the interactions between stator unit and rotor. In this review, we summarize recent advances in our understanding of the structure and function of the flagellar stator unit, torque generation, and directional switching of the motor.
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Affiliation(s)
- Haidai Hu
- Structural Biology of Molecular Machines Group, Protein Structure & Function Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Mònica Santiveri
- Structural Biology of Molecular Machines Group, Protein Structure & Function Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Navish Wadhwa
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA; Rowland Institute at Harvard, Harvard University, 100 Edwin H. Land Blvd, Cambridge, MA 02142, USA
| | - Howard C Berg
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA; Rowland Institute at Harvard, Harvard University, 100 Edwin H. Land Blvd, Cambridge, MA 02142, USA
| | - Marc Erhardt
- Institut für Biologie/Bakterienphysiologie, Humboldt-Universität zu Berlin, Philippstr. 13, 10115 Berlin, Germany
| | - Nicholas M I Taylor
- Structural Biology of Molecular Machines Group, Protein Structure & Function Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark.
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23
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Ferreira JL, Coleman I, Addison ML, Zachs T, Quigley BL, Wuichet K, Beeby M. The "Jack-of-all-Trades" Flagellum From Salmonella and E. coli Was Horizontally Acquired From an Ancestral β-Proteobacterium. Front Microbiol 2021; 12:643180. [PMID: 33859630 PMCID: PMC8042155 DOI: 10.3389/fmicb.2021.643180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/05/2021] [Indexed: 11/24/2022] Open
Abstract
The γ-proteobacteria are a group of diverse bacteria including pathogenic Escherichia, Salmonella, Vibrio, and Pseudomonas species. The majority swim in liquids with polar, sodium-driven flagella and swarm on surfaces with lateral, non-chemotactic flagella. Notable exceptions are the enteric Enterobacteriaceae such as Salmonella and E. coli. Many of the well-studied Enterobacteriaceae are gut bacteria that both swim and swarm with the same proton-driven peritrichous flagella. How different flagella evolved in closely related lineages, however, has remained unclear. Here, we describe our phylogenetic finding that Enterobacteriaceae flagella are not native polar or lateral γ-proteobacterial flagella but were horizontally acquired from an ancestral β-proteobacterium. Using electron cryo-tomography and subtomogram averaging, we confirmed that Enterobacteriaceae flagellar motors resemble contemporary β-proteobacterial motors and are distinct to the polar and lateral motors of other γ-proteobacteria. Structural comparisons support a model in which γ-proteobacterial motors have specialized, suggesting that acquisition of a β-proteobacterial flagellum may have been beneficial as a general-purpose motor suitable for adjusting to diverse conditions. This acquisition may have played a role in the development of the enteric lifestyle.
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Affiliation(s)
- Josie L Ferreira
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Izaak Coleman
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Max L Addison
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Tobias Zachs
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Bonnie L Quigley
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Kristin Wuichet
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Morgan Beeby
- Department of Life Sciences, Imperial College London, London, United Kingdom
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24
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Chang Y, Carroll BL, Liu J. Structural basis of bacterial flagellar motor rotation and switching. Trends Microbiol 2021; 29:1024-1033. [PMID: 33865677 DOI: 10.1016/j.tim.2021.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/11/2021] [Accepted: 03/16/2021] [Indexed: 01/08/2023]
Abstract
The bacterial flagellar motor, a remarkable rotary machine, can rapidly switch between counterclockwise (CCW) and clockwise (CW) rotational directions to control the migration behavior of the bacterial cell. The flagellar motor consists of a bidirectional spinning rotor surrounded by torque-generating stator units. Recent high-resolution in vitro and in situ structural studies have revealed stunning details of the individual components of the flagellar motor and their interactions in both the CCW and CW senses. In this review, we discuss these structures and their implications for understanding the molecular mechanisms underlying flagellar rotation and switching.
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Affiliation(s)
- Yunjie Chang
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06536, USA; Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA
| | - Brittany L Carroll
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06536, USA; Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06536, USA; Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA.
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25
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Zhou X, Roujeinikova A. The Structure, Composition, and Role of Periplasmic Stator Scaffolds in Polar Bacterial Flagellar Motors. Front Microbiol 2021; 12:639490. [PMID: 33776972 PMCID: PMC7990780 DOI: 10.3389/fmicb.2021.639490] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/16/2021] [Indexed: 01/10/2023] Open
Abstract
In the bacterial flagellar motor, the cell-wall-anchored stator uses an electrochemical gradient across the cytoplasmic membrane to generate a turning force that is applied to the rotor connected to the flagellar filament. Existing theoretical concepts for the stator function are based on the assumption that it anchors around the rotor perimeter by binding to peptidoglycan (P). The existence of another anchoring region on the motor itself has been speculated upon, but is yet to be supported by binding studies. Due to the recent advances in electron cryotomography, evidence has emerged that polar flagellar motors contain substantial proteinaceous periplasmic structures next to the stator, without which the stator does not assemble and the motor does not function. These structures have a morphology of disks, as is the case with Vibrio spp., or a round cage, as is the case with Helicobacter pylori. It is now recognized that such additional periplasmic components are a common feature of polar flagellar motors, which sustain higher torque and greater swimming speeds compared to peritrichous bacteria such as Escherichia coli and Salmonella enterica. This review summarizes the data available on the structure, composition, and role of the periplasmic scaffold in polar bacterial flagellar motors and discusses the new paradigm for how such motors assemble and function.
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Affiliation(s)
- Xiaotian Zhou
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Anna Roujeinikova
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Department of Microbiology, Monash University, Clayton, VIC, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
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26
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Vroom MM, Rodriguez-Ocasio Y, Lynch JB, Ruby EG, Foster JS. Modeled microgravity alters lipopolysaccharide and outer membrane vesicle production of the beneficial symbiont Vibrio fischeri. NPJ Microgravity 2021; 7:8. [PMID: 33686090 PMCID: PMC7940393 DOI: 10.1038/s41526-021-00138-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 02/02/2021] [Indexed: 01/04/2023] Open
Abstract
Reduced gravity, or microgravity, can have a pronounced impact on the physiology of animals, but the effects on their associated microbiomes are not well understood. Here, the impact of modeled microgravity on the shedding of Gram-negative lipopolysaccharides (LPS) by the symbiotic bacterium Vibrio fischeri was examined using high-aspect ratio vessels. LPS from V. fischeri is known to induce developmental apoptosis within its symbiotic tissues, which is accelerated under modeled microgravity conditions. In this study, we provide evidence that exposure to modeled microgravity increases the amount of LPS released by the bacterial symbiont in vitro. The higher rates of shedding under modeled microgravity conditions are associated with increased production of outer-membrane vesicles (OMV), which has been previously correlated to flagellar motility. Mutants of V. fischeri defective in the production and rotation of their flagella show significant decreases in LPS shedding in all treatments, but levels of LPS are higher under modeled microgravity despite loss of motility. Modeled microgravity also appears to affect the outer-membrane integrity of V. fischeri, as cells incubated under modeled microgravity conditions are more susceptible to cell-membrane-disrupting agents. These results suggest that, like their animal hosts, the physiology of symbiotic microbes can be altered under microgravity-like conditions, which may have important implications for host health during spaceflight.
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Affiliation(s)
- Madeline M Vroom
- Department of Microbiology and Cell Science, Space Life Science Lab, University of Florida, Merritt Island, FL, USA
| | - Yaneli Rodriguez-Ocasio
- Department of Microbiology and Cell Science, Space Life Science Lab, University of Florida, Merritt Island, FL, USA
| | - Jonathan B Lynch
- Pacific Biosciences Research Center, Kewalo Marine Laboratory, University of Hawai'i at Manoa, Honolulu, HI, USA.,Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, USA
| | - Edward G Ruby
- Pacific Biosciences Research Center, Kewalo Marine Laboratory, University of Hawai'i at Manoa, Honolulu, HI, USA
| | - Jamie S Foster
- Department of Microbiology and Cell Science, Space Life Science Lab, University of Florida, Merritt Island, FL, USA.
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27
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Nishikino T, Kojima S, Homma M. [Flagellar related genes and functions in Vibrio]. Nihon Saikingaku Zasshi 2021; 75:195-214. [PMID: 33390367 DOI: 10.3412/jsb.75.195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Bacteria can move or swim by flagella. On the other hand, the motile ability is not necessary to live at all. In laboratory, the flagella-deficient strains can grow just like the wild-type strains. The flagellum is assembled from more than 20 structural proteins and there are more than 50 genes including the structural genes to regulate or support the flagellar formation. The cost to construct the flagellum is so expensive. The fact that it evolved as a motor organ means even at such the large cost shows that the flagellum is essential for survival in natural condition. In this review, we would like to focus on the flagella-related researches conducted by the authors and the flagellar research on Vibrio spp.
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Affiliation(s)
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University
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28
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Milne-Davies B, Wimmi S, Diepold A. Adaptivity and dynamics in type III secretion systems. Mol Microbiol 2020; 115:395-411. [PMID: 33251695 DOI: 10.1111/mmi.14658] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/17/2020] [Accepted: 11/23/2020] [Indexed: 01/07/2023]
Abstract
The type III secretion system is the common core of two bacterial molecular machines: the flagellum and the injectisome. The flagellum is the most widely distributed prokaryotic locomotion device, whereas the injectisome is a syringe-like apparatus for inter-kingdom protein translocation, which is essential for virulence in important human pathogens. The successful concept of the type III secretion system has been modified for different bacterial needs. It can be adapted to changing conditions, and was found to be a dynamic complex constantly exchanging components. In this review, we highlight the flexibility, adaptivity, and dynamic nature of the type III secretion system.
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Affiliation(s)
- Bailey Milne-Davies
- Department of Ecophysiology, Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany
| | - Stephan Wimmi
- Department of Ecophysiology, Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany
| | - Andreas Diepold
- Department of Ecophysiology, Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany
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29
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Umrekar TR, Cohen E, Drobnič T, Gonzalez-Rodriguez N, Beeby M. CryoEM of bacterial secretion systems: A primer for microbiologists. Mol Microbiol 2020; 115:366-382. [PMID: 33140482 DOI: 10.1111/mmi.14637] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/27/2020] [Accepted: 10/29/2020] [Indexed: 12/11/2022]
Abstract
"CryoEM" has come of age, enabling considerable structural insights into many facets of molecular biology. Here, we present a primer for microbiologists to understand the capabilities and limitations of two complementary cryoEM techniques for studying bacterial secretion systems. The first, single particle analysis, determines the structures of purified protein complexes to resolutions sufficient for molecular modeling, while the second, electron cryotomography and subtomogram averaging, tends to determine more modest resolution structures of protein complexes in intact cells. We illustrate these abilities with examples of insights provided into how secretion systems work by cryoEM, with a focus on type III secretion systems.
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Affiliation(s)
| | - Eli Cohen
- Department of Life Sciences, Imperial College London, London, UK
| | - Tina Drobnič
- Department of Life Sciences, Imperial College London, London, UK
| | | | - Morgan Beeby
- Department of Life Sciences, Imperial College London, London, UK
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30
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Structural Conservation and Adaptation of the Bacterial Flagella Motor. Biomolecules 2020; 10:biom10111492. [PMID: 33138111 PMCID: PMC7693769 DOI: 10.3390/biom10111492] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 02/07/2023] Open
Abstract
Many bacteria require flagella for the ability to move, survive, and cause infection. The flagellum is a complex nanomachine that has evolved to increase the fitness of each bacterium to diverse environments. Over several decades, molecular, biochemical, and structural insights into the flagella have led to a comprehensive understanding of the structure and function of this fascinating nanomachine. Notably, X-ray crystallography, cryo-electron microscopy (cryo-EM), and cryo-electron tomography (cryo-ET) have elucidated the flagella and their components to unprecedented resolution, gleaning insights into their structural conservation and adaptation. In this review, we focus on recent structural studies that have led to a mechanistic understanding of flagellar assembly, function, and evolution.
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31
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Carroll BL, Nishikino T, Guo W, Zhu S, Kojima S, Homma M, Liu J. The flagellar motor of Vibrio alginolyticus undergoes major structural remodeling during rotational switching. eLife 2020; 9:61446. [PMID: 32893817 PMCID: PMC7505661 DOI: 10.7554/elife.61446] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 09/04/2020] [Indexed: 11/26/2022] Open
Abstract
The bacterial flagellar motor switches rotational direction between counterclockwise (CCW) and clockwise (CW) to direct the migration of the cell. The cytoplasmic ring (C-ring) of the motor, which is composed of FliG, FliM, and FliN, is known for controlling the rotational sense of the flagellum. However, the mechanism underlying rotational switching remains elusive. Here, we deployed cryo-electron tomography to visualize the C-ring in two rotational biased mutants in Vibrio alginolyticus. We determined the C-ring molecular architectures, providing novel insights into the mechanism of rotational switching. We report that the C-ring maintained 34-fold symmetry in both rotational senses, and the protein composition remained constant. The two structures show FliG conformational changes elicit a large conformational rearrangement of the rotor complex that coincides with rotational switching of the flagellum. FliM and FliN form a stable spiral-shaped base of the C-ring, likely stabilizing the C-ring during the conformational remodeling.
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Affiliation(s)
- Brittany L Carroll
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, United States.,Microbial Sciences Institute, Yale University, West Haven, United States
| | - Tatsuro Nishikino
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan
| | - Wangbiao Guo
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, United States.,Microbial Sciences Institute, Yale University, West Haven, United States
| | - Shiwei Zhu
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, United States.,Microbial Sciences Institute, Yale University, West Haven, United States
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, United States.,Microbial Sciences Institute, Yale University, West Haven, United States
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32
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Structure and Energy-Conversion Mechanism of the Bacterial Na+-Driven Flagellar Motor. Trends Microbiol 2020; 28:719-731. [DOI: 10.1016/j.tim.2020.03.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/16/2020] [Accepted: 03/25/2020] [Indexed: 01/09/2023]
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33
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Rossmann FM, Hug I, Sangermani M, Jenal U, Beeby M. In situ structure of the Caulobacter crescentus flagellar motor and visualization of binding of a CheY-homolog. Mol Microbiol 2020; 114:443-453. [PMID: 32449846 PMCID: PMC7534056 DOI: 10.1111/mmi.14525] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/30/2020] [Accepted: 05/04/2020] [Indexed: 12/30/2022]
Abstract
Bacterial flagellar motility is controlled by the binding of CheY proteins to the cytoplasmic switch complex of the flagellar motor, resulting in changes in swimming speed or direction. Despite its importance for motor function, structural information about the interaction between effector proteins and the motor are scarce. To address this gap in knowledge, we used electron cryotomography and subtomogram averaging to visualize such interactions inside Caulobacter crescentus cells. In C. crescentus, several CheY homologs regulate motor function for different aspects of the bacterial lifestyle. We used subtomogram averaging to image binding of the CheY family protein CleD to the cytoplasmic Cring switch complex, the control center of the flagellar motor. This unambiguously confirmed the orientation of the motor switch protein FliM and the binding of a member of the CheY protein family to the outside rim of the C ring. We also uncovered previously unknown structural elaborations of the alphaproteobacterial flagellar motor, including two novel periplasmic ring structures, and the stator ring harboring eleven stator units, adding to our growing catalog of bacterial flagellar diversity.
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Affiliation(s)
| | - Isabelle Hug
- Focal Area of Infection BiologyBiozentrum of the University of BaselBaselSwitzerland
| | - Matteo Sangermani
- Focal Area of Infection BiologyBiozentrum of the University of BaselBaselSwitzerland
| | - Urs Jenal
- Focal Area of Infection BiologyBiozentrum of the University of BaselBaselSwitzerland
| | - Morgan Beeby
- Department of Life SciencesImperial College LondonLondonUK
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34
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Liu R, Zheng R, Liu G, Sun C. The cyclic lipopeptides suppress the motility of Vibrio alginolyticus via targeting the Na + -driven flagellar motor component MotX. Environ Microbiol 2020; 22:4424-4437. [PMID: 32608186 DOI: 10.1111/1462-2920.15144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/18/2020] [Accepted: 06/28/2020] [Indexed: 01/17/2023]
Abstract
In our previous study, we found that pumilacidin-like cyclic lipopeptides (CLPs) derived from marine bacterium Bacillus sp. strain 176 significantly suppressed the mobile capability and virulence of Vibrio alginolyticus. Here, to further disclose the mechanism of CLPs inhibiting the motility of V. alginolyticus, we first applied transcriptomic analysis to V. alginolyticus treated with or without CLPs. The transcriptomic results showed that the expression of several important components of the Na+ -driven flagellar motor closely related to bacterial motility were markedly suppressed, suggesting that the structure and function of Na+ -driven flagellar motor might be disabled by CLPs. The transcriptomic data were further analysed by the protein-protein interaction network, and the results supported that MotX, one of the essential components of Na+ -driven flagellar motor was most likely the action target of CLPs. In combination of gene knockout, electrophoretic mobility shift assay and immunoblotting techniques, CLPs were demonstrated to affect the rotation of flagella of Vibrio alginolyticus via direct interacting with the Na+ -driven flagellar motor component MotX, which eventually inhibited the bacterial motility. Interestingly, homologues of MotX were found broadly distributed and highly conserved in different pathogenic species, which extends the application range of CLPs as an antibacterial drug targeting bacterial motility in many pathogens.
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Affiliation(s)
- Rui Liu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.,College of Earth Science, University of Chinese Academy of Sciences, Beijing, China
| | - Rikuan Zheng
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.,College of Earth Science, University of Chinese Academy of Sciences, Beijing, China.,Center of Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Ge Liu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.,College of Earth Science, University of Chinese Academy of Sciences, Beijing, China
| | - Chaomin Sun
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.,College of Earth Science, University of Chinese Academy of Sciences, Beijing, China
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35
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Chieffi D, Fanelli F, Fusco V. Arcobacter butzleri: Up-to-date taxonomy, ecology, and pathogenicity of an emerging pathogen. Compr Rev Food Sci Food Saf 2020; 19:2071-2109. [PMID: 33337088 DOI: 10.1111/1541-4337.12577] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 04/22/2020] [Accepted: 04/22/2020] [Indexed: 12/19/2022]
Abstract
Arcobacter butzleri, recently emended to the Aliarcobacter butzleri comb. nov., is an emerging pathogen causing enteritis, severe diarrhea, septicaemia, and bacteraemia in humans and enteritis, stillbirth, and abortion in animals. Since its recognition as emerging pathogen on 2002, advancements have been made in elucidating its pathogenicity and epidemiology, also thanks to advent of genomics, which, moreover, contributed in emending its taxonomy. In this review, we provide an overview of the up-to-date taxonomy, ecology, and pathogenicity of this emerging pathogen. Moreover, the implication of A. butzleri in the safety of foods is pinpointed, and culture-dependent and independent detection, identification, and typing methods as well as strategies to control and prevent the survival and growth of this pathogen are provided.
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Affiliation(s)
- Daniele Chieffi
- Institute of Sciences of Food Production, National Research Council of Italy (CNR-ISPA), Bari, Italy
| | - Francesca Fanelli
- Institute of Sciences of Food Production, National Research Council of Italy (CNR-ISPA), Bari, Italy
| | - Vincenzina Fusco
- Institute of Sciences of Food Production, National Research Council of Italy (CNR-ISPA), Bari, Italy
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36
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Camarena L, Dreyfus G. Living in a Foster Home: The Single Subpolar Flagellum Fla1 of Rhodobacter sphaeroides. Biomolecules 2020; 10:E774. [PMID: 32429424 PMCID: PMC7277832 DOI: 10.3390/biom10050774] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 05/12/2020] [Accepted: 05/13/2020] [Indexed: 12/14/2022] Open
Abstract
Rhodobacter sphaeroides is an α-proteobacterium that has the particularity of having two functional flagellar systems used for swimming. Under the growth conditions commonly used in the laboratory, a single subpolar flagellum that traverses the cell membrane, is assembled on the surface. This flagellum has been named Fla1. Phylogenetic analyses have suggested that this flagellar genetic system was acquired from an ancient γ-proteobacterium. It has been shown that this flagellum has components homologous to those present in other γ-proteobacteria such as the H-ring characteristic of the Vibrio species. Other features of this flagellum such as a straight hook, and a prominent HAP region have been studied and the molecular basis underlying these features has been revealed. It has also been shown that FliL, and the protein MotF, mainly found in several species of the family Rhodobacteraceae, contribute to remodel the amphipathic region of MotB, known as the plug, in order to allow flagellar rotation. In the absence of the plug region of MotB, FliL and MotF are dispensable. In this review we have covered the most relevant aspects of the Fla1 flagellum of this remarkable photosynthetic bacterium.
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Affiliation(s)
- Laura Camarena
- Depto. Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, CDMX 04510, Mexico
| | - Georges Dreyfus
- Depto. Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, CDMX 04510, Mexico
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37
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Zhuang X, Guo S, Li Z, Zhao Z, Kojima S, Homma M, Wang P, Lo C, Bai F. Live‐cell fluorescence imaging reveals dynamic production and loss of bacterial flagella. Mol Microbiol 2020; 114:279-291. [DOI: 10.1111/mmi.14511] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/10/2020] [Accepted: 03/30/2020] [Indexed: 02/02/2023]
Affiliation(s)
- Xiang‐Yu Zhuang
- Department of Physics and Graduate Institute of Biophysics National Central University Jhongli Taiwan, R.O.C
| | - Shihao Guo
- Biomedical Pioneering Innovation Center (BIOPIC) School of Life Sciences Peking University Beijing China
- Department of General Surgery Peking University First Hospital Peking University Beijing China
| | - Zhuoran Li
- Biomedical Pioneering Innovation Center (BIOPIC) School of Life Sciences Peking University Beijing China
| | - Ziyi Zhao
- Biomedical Pioneering Innovation Center (BIOPIC) School of Life Sciences Peking University Beijing China
| | - Seiji Kojima
- Division of Biological Science Graduate School of Science Nagoya University Nagoya Japan
| | - Michio Homma
- Division of Biological Science Graduate School of Science Nagoya University Nagoya Japan
| | - Pengyuan Wang
- Department of General Surgery Peking University First Hospital Peking University Beijing China
| | - Chien‐Jung Lo
- Department of Physics and Graduate Institute of Biophysics National Central University Jhongli Taiwan, R.O.C
| | - Fan Bai
- Biomedical Pioneering Innovation Center (BIOPIC) School of Life Sciences Peking University Beijing China
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38
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Bacterial flagellar motor PL-ring disassembly subcomplexes are widespread and ancient. Proc Natl Acad Sci U S A 2020; 117:8941-8947. [PMID: 32241888 PMCID: PMC7183148 DOI: 10.1073/pnas.1916935117] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
In order to understand the evolution of complex biological machines like the bacterial flagellar motor, it is crucial to know what each component does and when it arose. Here, we show that a subcomplex of the motor thought to act as a bushing for the spinning motor likely also serves another function—it plugs the hole in the outer membrane left when the flagellum disassembles. Moreover, this component and function is ancient, since it appears in diverse phyla without evidence of recent gene transfer. The bacterial flagellum is an amazing nanomachine. Understanding how such complex structures arose is crucial to our understanding of cellular evolution. We and others recently reported that in several Gammaproteobacterial species, a relic subcomplex comprising the decorated P and L rings persists in the outer membrane after flagellum disassembly. Imaging nine additional species with cryo-electron tomography, here, we show that this subcomplex persists after flagellum disassembly in other phyla as well. Bioinformatic analyses fail to show evidence of any recent horizontal transfers of the P- and L-ring genes, suggesting that this subcomplex and its persistence is an ancient and conserved feature of the flagellar motor. We hypothesize that one function of the P and L rings is to seal the outer membrane after motor disassembly.
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39
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Reciprocal c-di-GMP signaling: Incomplete flagellum biogenesis triggers c-di-GMP signaling pathways that promote biofilm formation. PLoS Genet 2020; 16:e1008703. [PMID: 32176702 PMCID: PMC7098655 DOI: 10.1371/journal.pgen.1008703] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 03/26/2020] [Accepted: 03/01/2020] [Indexed: 11/25/2022] Open
Abstract
The assembly status of the V. cholerae flagellum regulates biofilm formation, suggesting that the bacterium senses a lack of movement to commit to a sessile lifestyle. Motility and biofilm formation are inversely regulated by the second messenger molecule cyclic dimeric guanosine monophosphate (c-di-GMP). Therefore, we sought to define the flagellum-associated c-di-GMP-mediated signaling pathways that regulate the transition from a motile to a sessile state. Here we report that elimination of the flagellum, via loss of the FlaA flagellin, results in a flagellum-dependent biofilm regulatory (FDBR) response, which elevates cellular c-di-GMP levels, increases biofilm gene expression, and enhances biofilm formation. The strength of the FDBR response is linked with status of the flagellar stator: it can be reversed by deletion of the T ring component MotX, and reduced by mutations altering either the Na+ binding ability of the stator or the Na+ motive force. Absence of the stator also results in reduction of mannose-sensitive hemagglutinin (MSHA) pilus levels on the cell surface, suggesting interconnectivity of signal transduction pathways involved in biofilm formation. Strains lacking flagellar rotor components similarly launched an FDBR response, however this was independent of the status of assembly of the flagellar stator. We found that the FDBR response requires at least three specific diguanylate cyclases that contribute to increased c-di-GMP levels, and propose that activation of biofilm formation during this response relies on c-di-GMP-dependent activation of positive regulators of biofilm production. Together our results dissect how flagellum assembly activates c-di-GMP signaling circuits, and how V. cholerae utilizes these signals to transition from a motile to a sessile state. A key regulator of Vibrio cholerae physiology is the nucleotide-based, second messenger cyclic dimeric guanosine monophosphate (c-di-GMP). We found that the status of flagellar biosynthesis at different stages of flagellar assembly modulates c-di-GMP signaling in V. cholerae and identified diguanylate cyclases involved in this regulatory process. The effect of motility status on the cellular c-di-GMP level is partly dependent on the flagellar stator and Na+ flux through the flagellum. Finally, we showed that c-di-GMP-dependent positive regulators of biofilm formation are critical for the signaling cascade that connects motility status to biofilm formation. Our results show that in addition to c-di-GMP promoting motile to biofilm lifestyle switch, “motility status” of V. cholerae modulates c-di-GMP signaling and biofilm formation.
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Beeby M, Ferreira JL, Tripp P, Albers SV, Mitchell DR. Propulsive nanomachines: the convergent evolution of archaella, flagella and cilia. FEMS Microbiol Rev 2020; 44:253-304. [DOI: 10.1093/femsre/fuaa006] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 03/06/2020] [Indexed: 02/06/2023] Open
Abstract
ABSTRACT
Echoing the repeated convergent evolution of flight and vision in large eukaryotes, propulsive swimming motility has evolved independently in microbes in each of the three domains of life. Filamentous appendages – archaella in Archaea, flagella in Bacteria and cilia in Eukaryotes – wave, whip or rotate to propel microbes, overcoming diffusion and enabling colonization of new environments. The implementations of the three propulsive nanomachines are distinct, however: archaella and flagella rotate, while cilia beat or wave; flagella and cilia assemble at their tips, while archaella assemble at their base; archaella and cilia use ATP for motility, while flagella use ion-motive force. These underlying differences reflect the tinkering required to evolve a molecular machine, in which pre-existing machines in the appropriate contexts were iteratively co-opted for new functions and whose origins are reflected in their resultant mechanisms. Contemporary homologies suggest that archaella evolved from a non-rotary pilus, flagella from a non-rotary appendage or secretion system, and cilia from a passive sensory structure. Here, we review the structure, assembly, mechanism and homologies of the three distinct solutions as a foundation to better understand how propulsive nanomachines evolved three times independently and to highlight principles of molecular evolution.
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Affiliation(s)
- Morgan Beeby
- Department of Life Sciences, Frankland Road, Imperial College of London, London, SW7 2AZ, UK
| | - Josie L Ferreira
- Department of Life Sciences, Frankland Road, Imperial College of London, London, SW7 2AZ, UK
| | - Patrick Tripp
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Schaenzlestrasse 1, 79211 Freiburg, Germany
| | - Sonja-Verena Albers
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Schaenzlestrasse 1, 79211 Freiburg, Germany
| | - David R Mitchell
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA
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Chu J, Liu J, Hoover TR. Phylogenetic Distribution, Ultrastructure, and Function of Bacterial Flagellar Sheaths. Biomolecules 2020; 10:biom10030363. [PMID: 32120823 PMCID: PMC7175336 DOI: 10.3390/biom10030363] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/25/2020] [Accepted: 02/26/2020] [Indexed: 02/06/2023] Open
Abstract
A number of Gram-negative bacteria have a membrane surrounding their flagella, referred to as the flagellar sheath, which is continuous with the outer membrane. The flagellar sheath was initially described in Vibrio metschnikovii in the early 1950s as an extension of the outer cell wall layer that completely surrounded the flagellar filament. Subsequent studies identified other bacteria that possess flagellar sheaths, most of which are restricted to a few genera of the phylum Proteobacteria. Biochemical analysis of the flagellar sheaths from a few bacterial species revealed the presence of lipopolysaccharide, phospholipids, and outer membrane proteins in the sheath. Some proteins localize preferentially to the flagellar sheath, indicating mechanisms exist for protein partitioning to the sheath. Recent cryo-electron tomography studies have yielded high resolution images of the flagellar sheath and other structures closely associated with the sheath, which has generated insights and new hypotheses for how the flagellar sheath is synthesized. Various functions have been proposed for the flagellar sheath, including preventing disassociation of the flagellin subunits in the presence of gastric acid, avoiding activation of the host innate immune response by flagellin, activating the host immune response, adherence to host cells, and protecting the bacterium from bacteriophages.
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Affiliation(s)
- Joshua Chu
- Department of Microbiology, Cornell University, Ithaca, NY 14853, USA;
| | - Jun Liu
- Microbial Sciences Institute, Department of Microbial Pathogenesis, Yale University, West Haven, CT 06516, USA;
| | - Timothy R. Hoover
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
- Correspondence: ; Tel.: +1-706-542-2675
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Abstract
Periplasmic flagella are complex nanomachines responsible for distinctive morphology and motility of spirochetes. Although bacterial flagella have been extensively studied for several decades in the model systems Escherichia coli and Salmonella enterica, our understanding of periplasmic flagella in many disease-causing spirochetes remains incomplete. Recent advances, including molecular genetics, biochemistry, structural biology, and cryo-electron tomography, have greatly increased our understanding of structure and function of periplasmic flagella. In this chapter, we summarize some of the recent findings that provide new insights into the structure, assembly, and function of periplasmic flagella.
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In Situ Structure of the Vibrio Polar Flagellum Reveals a Distinct Outer Membrane Complex and Its Specific Interaction with the Stator. J Bacteriol 2020; 202:JB.00592-19. [PMID: 31767780 DOI: 10.1128/jb.00592-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Accepted: 11/18/2019] [Indexed: 01/01/2023] Open
Abstract
The bacterial flagellum is a biological nanomachine that rotates to allow bacteria to swim. For flagellar rotation, torque is generated by interactions between a rotor and a stator. The stator, which is composed of MotA and MotB subunit proteins in the membrane, is thought to bind to the peptidoglycan (PG) layer, which anchors the stator around the rotor. Detailed information on the stator and its interactions with the rotor remains unclear. Here, we deployed cryo-electron tomography and genetic analysis to characterize in situ structure of the bacterial flagellar motor in Vibrio alginolyticus, which is best known for its polar sheathed flagellum and high-speed rotation. We determined in situ structure of the motor at unprecedented resolution and revealed the unique protein-protein interactions among Vibrio-specific features, namely the H ring and T ring. Specifically, the H ring is composed of 26 copies of FlgT and FlgO, and the T ring consists of 26 copies of a MotX-MotY heterodimer. We revealed for the first time a specific interaction between the T ring and the stator PomB subunit, providing direct evidence that the stator unit undergoes a large conformational change from a compact form to an extended form. The T ring facilitates the recruitment of the extended stator units for the high-speed motility in Vibrio species.IMPORTANCE The torque of flagellar rotation is generated by interactions between a rotor and a stator; however, detailed structural information is lacking. Here, we utilized cryo-electron tomography and advanced imaging analysis to obtain a high-resolution in situ flagellar basal body structure in Vibrio alginolyticus, which is a Gram-negative marine bacterium. Our high-resolution motor structure not only revealed detailed protein-protein interactions among unique Vibrio-specific features, the T ring and H ring, but also provided the first structural evidence that the T ring interacts directly with the periplasmic domain of the stator. Docking atomic structures of key components into the in situ motor map allowed us to visualize the pseudoatomic architecture of the polar sheathed flagellum in Vibrio spp. and provides novel insight into its assembly and function.
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44
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Fanelli F, Chieffi D, Di Pinto A, Mottola A, Baruzzi F, Fusco V. Phenotype and genomic background of Arcobacter butzleri strains and taxogenomic assessment of the species. Food Microbiol 2020; 89:103416. [PMID: 32138986 DOI: 10.1016/j.fm.2020.103416] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/08/2019] [Accepted: 01/08/2020] [Indexed: 11/29/2022]
Abstract
In this study the phenotypic and genomic characterization of two Arcobacter butzleri (Ab) strains (Ab 34_O and Ab 39_O) isolated from pre-cut ready-to-eat vegetables were performed. Results provided useful data about their taxonomy and their overall virulence potential with particular reference to the antibiotic and heavy metal susceptibility. These features were moreover compared with those of two Ab strains isolated from shellfish and a genotaxonomic assessment of the Ab species was performed. The two Ab isolated from vegetables were confirmed to belong to the Aliarcobacter butzleri species by 16S rRNA gene sequence analysis, MLST and genomic analyses. The genome-based taxonomic assessment of the Ab species brought to the light the possibility to define different subspecies reflecting the source of isolation, even though further genomes from different sources should be available to support this hypothesis. The strains isolated from vegetables in the same geographic area shared the same distribution of COGs with a prevalence of the cluster "inorganic ion transport and metabolism", consistent with the lithotrophic nature of Arcobacter spp. None of the Ab strains (from shellfish and from vegetables) metabolized carbohydrates but utilized organic acids and amino acids as carbon sources. The metabolic fingerprinting of Ab resulted less discriminatory than the genome-based approach. The Ab strains isolated from vegetables and those isolated from shellfish endowed multiple resistance to several antibiotics and heavy metals.
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Affiliation(s)
- Francesca Fanelli
- Institute of Sciences of Food Production of the National Research Council of Italy (CNR-ISPA), Bari, 70126, Italy
| | - Daniele Chieffi
- Institute of Sciences of Food Production of the National Research Council of Italy (CNR-ISPA), Bari, 70126, Italy
| | - Angela Di Pinto
- Department of Veterinary Medicine, University of Bari Aldo Moro, Valenzano, Bari, 70010, Italy
| | - Anna Mottola
- Department of Veterinary Medicine, University of Bari Aldo Moro, Valenzano, Bari, 70010, Italy
| | - Federico Baruzzi
- Institute of Sciences of Food Production of the National Research Council of Italy (CNR-ISPA), Bari, 70126, Italy
| | - Vincenzina Fusco
- Institute of Sciences of Food Production of the National Research Council of Italy (CNR-ISPA), Bari, 70126, Italy.
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45
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Schniederberend M, Williams JF, Shine E, Shen C, Jain R, Emonet T, Kazmierczak BI. Modulation of flagellar rotation in surface-attached bacteria: A pathway for rapid surface-sensing after flagellar attachment. PLoS Pathog 2019; 15:e1008149. [PMID: 31682637 PMCID: PMC6855561 DOI: 10.1371/journal.ppat.1008149] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 11/14/2019] [Accepted: 10/16/2019] [Indexed: 12/11/2022] Open
Abstract
Attachment is a necessary first step in bacterial commitment to surface-associated behaviors that include colonization, biofilm formation, and host-directed virulence. The Gram-negative opportunistic pathogen Pseudomonas aeruginosa can initially attach to surfaces via its single polar flagellum. Although many bacteria quickly detach, some become irreversibly attached and express surface-associated structures, such as Type IV pili, and behaviors, including twitching motility and biofilm initiation. P. aeruginosa that lack the GTPase FlhF assemble a randomly placed flagellum that is motile; however, we observed that these mutant bacteria show defects in biofilm formation comparable to those seen for non-motile, aflagellate bacteria. This phenotype was associated with altered behavior of ΔflhF bacteria immediately following surface-attachment. Forward and reverse genetic screens led to the discovery that FlhF interacts with FimV to control flagellar rotation at a surface, and implicated cAMP signaling in this pathway. Although cAMP controls many transcriptional programs in P. aeruginosa, known targets of this second messenger were not required to modulate flagellar rotation in surface-attached bacteria. Instead, alterations in switching behavior of the motor appeared to result from direct or indirect effects of cAMP on switch complex proteins and/or the stators associated with them.
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Affiliation(s)
- Maren Schniederberend
- Department of Medicine (Infectious Diseases), Yale University, New Haven, Connecticut, United States of America
| | - Jessica F. Williams
- Department of Molecular, Cellular & Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Emilee Shine
- Program in Microbiology, Yale University, New Haven, Connecticut, United States of America
| | - Cong Shen
- Program in Microbiology, Yale University, New Haven, Connecticut, United States of America
| | - Ruchi Jain
- Department of Medicine (Infectious Diseases), Yale University, New Haven, Connecticut, United States of America
| | - Thierry Emonet
- Department of Molecular, Cellular & Developmental Biology, Yale University, New Haven, Connecticut, United States of America
- Department of Physics, Yale University, New Haven, Connecticut, United States of America
| | - Barbara I. Kazmierczak
- Department of Medicine (Infectious Diseases), Yale University, New Haven, Connecticut, United States of America
- Department of Microbial Pathogenesis, Yale University, New Haven, Connecticut, United States of America
- * E-mail:
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46
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Aschtgen MS, Brennan CA, Nikolakakis K, Cohen S, McFall-Ngai M, Ruby EG. Insights into flagellar function and mechanism from the squid-vibrio symbiosis. NPJ Biofilms Microbiomes 2019; 5:32. [PMID: 31666982 PMCID: PMC6814793 DOI: 10.1038/s41522-019-0106-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 10/03/2019] [Indexed: 02/07/2023] Open
Abstract
Flagella are essential and multifunctional nanomachines that not only move symbionts towards their tissue colonization site, but also play multiple roles in communicating with the host. Thus, untangling the activities of flagella in reaching, interacting, and signaling the host, as well as in biofilm formation and the establishment of a persistent colonization, is a complex problem. The squid-vibrio system offers a unique model to study the many ways that bacterial flagella can influence a beneficial association and, generally, other bacteria-host interactions. Vibrio fischeri is a bioluminescent bacterium that colonizes the Hawaiian bobtail squid, Euprymna scolopes. Over the last 15 years, the structure, assembly, and functions of V. fischeri flagella, including not only motility and chemotaxis, but also biofilm formation and symbiotic signaling, have been revealed. Here we discuss these discoveries in the perspective of other host-bacteria interactions.
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Affiliation(s)
- Marie-Stephanie Aschtgen
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706 USA
- Present Address: Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Solna, 171 76 Sweden
| | - Caitlin A. Brennan
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706 USA
- Present Address: Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115 USA
| | - Kiel Nikolakakis
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706 USA
- Present Address: Department of Natural and Applied Sciences, University of Wisconsin – Green Bay, Green Bay, WI 54311 USA
| | - Stephanie Cohen
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, and Center for Advanced Surface Analysis, Institute of Earth Sciences, Université de Lausanne, CH-1015 Lausanne, Switzerland
- Kewalo Marine Laboratory, University of Hawaii-Manoa, Honolulu, HI 96813 USA
| | | | - Edward G. Ruby
- Kewalo Marine Laboratory, University of Hawaii-Manoa, Honolulu, HI 96813 USA
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47
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Mino T, Nishikino T, Iwatsuki H, Kojima S, Homma M. Effect of sodium ions on conformations of the cytoplasmic loop of the PomA stator protein of Vibrio alginolyticus. J Biochem 2019; 166:331-341. [PMID: 31147681 DOI: 10.1093/jb/mvz040] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 05/24/2019] [Indexed: 01/13/2023] Open
Abstract
The sodium driven flagellar stator of Vibrio alginolyticus is a hetero-hexamer membrane complex composed of PomA and PomB, and acts as a sodium ion channel. The conformational change in the cytoplasmic region of PomA for the flagellar torque generation, which interacts directly with a rotor protein, FliG, remains a mystery. In this study, we introduced cysteine mutations into cytoplasmic charged residues of PomA, which are highly conserved and interact with FliG, to detect the conformational change by the reactivity of biotin maleimide. In vivo labelling experiments of the PomA mutants revealed that the accessibility of biotin maleimide at position of E96 was reduced with sodium ions. Such a reduction was also seen in the D24N and the plug deletion mutants of PomB, and the phenomenon was independent in the presence of FliG. This sodium ions specific reduction was also detected in Escherichia coli that produced PomA and PomB from a plasmid, but not in the purified stator complex. These results demonstrated that sodium ions cause a conformational change around the E96 residue of loop2-3 in the biological membrane.
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Affiliation(s)
- Taira Mino
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Furo-cyo, Nagoya, Japan
| | - Tatsuro Nishikino
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Furo-cyo, Nagoya, Japan
| | - Hiroto Iwatsuki
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Furo-cyo, Nagoya, Japan
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Furo-cyo, Nagoya, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Furo-cyo, Nagoya, Japan
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48
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Kojima S, Yoneda T, Morimoto W, Homma M. Effect of PlzD, a YcgR homologue of c-di-GMP-binding protein, on polar flagellar motility in Vibrio alginolyticus. J Biochem 2019; 166:77-88. [PMID: 30778544 DOI: 10.1093/jb/mvz014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 02/14/2019] [Indexed: 01/01/2023] Open
Abstract
YcgR, a cyclic diguanylate (c-di-GMP)-binding protein expressed in Escherichia coli, brakes flagellar rotation by binding to the motor in a c-di-GMP dependent manner and has been implicated in triggering biofilm formation. Vibrio alginolyticus has a single polar flagellum and encodes YcgR homologue, PlzD. When PlzD or PlzD-GFP was highly over-produced in nutrient-poor condition, the polar flagellar motility of V. alginolyticus was reduced. This inhibitory effect is c-di-GMP independent as mutants substituting putative c-di-GMP-binding residues retain the effect. Moderate over-expression of PlzD-GFP allowed its localization at the flagellated cell pole. Truncation of the N-terminal 12 or 35 residues of PlzD abolished the inhibitory effect and polar localization, and no inhibitory effect was observed by deleting plzD or expressing an endogenous level of PlzD-GFP. Subcellular fractionation showed that PlzD, but not its N-terminally truncated variants, was precipitated when over-produced. Moreover, immunoblotting and N-terminal sequencing revealed that endogenous PlzD is synthesized from Met33. These results suggest that an N-terminal extension allows PlzD to localize at the cell pole but causes aggregation and leads to inhibition of motility. In V. alginolyticus, PlzD has a potential property to associate with the polar flagellar motor but this interaction is too weak to inhibit rotation.
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Affiliation(s)
- Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
| | - Takuro Yoneda
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
| | - Wakako Morimoto
- Department of Biological Science, School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
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49
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Chang Y, Moon KH, Zhao X, Norris SJ, Motaleb MA, Liu J. Structural insights into flagellar stator-rotor interactions. eLife 2019; 8:48979. [PMID: 31313986 PMCID: PMC6663468 DOI: 10.7554/elife.48979] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Accepted: 07/12/2019] [Indexed: 12/25/2022] Open
Abstract
The bacterial flagellar motor is a molecular machine that can rotate the flagellar filament at high speed. The rotation is generated by the stator–rotor interaction, coupled with an ion flux through the torque-generating stator. Here we employed cryo-electron tomography to visualize the intact flagellar motor in the Lyme disease spirochete, Borrelia burgdorferi. By analyzing the motor structures of wild-type and stator-deletion mutants, we not only localized the stator complex in situ, but also revealed the stator–rotor interaction at an unprecedented detail. Importantly, the stator–rotor interaction induces a conformational change in the flagella C-ring. Given our observation that a non-motile mutant, in which proton flux is blocked, cannot generate the similar conformational change, we propose that the proton-driven torque is responsible for the conformational change required for flagellar rotation.
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Affiliation(s)
- Yunjie Chang
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States.,Microbial Sciences Institute, Yale University, West Haven, United States
| | - Ki Hwan Moon
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States.,Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, United States
| | - Xiaowei Zhao
- Microbial Sciences Institute, Yale University, West Haven, United States.,Department of Pathology and Laboratory Medicine, McGovern Medical School at University of Texas Health Science Center at Houston, Houston, United States
| | - Steven J Norris
- Department of Pathology and Laboratory Medicine, McGovern Medical School at University of Texas Health Science Center at Houston, Houston, United States
| | - Md A Motaleb
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, United States
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States.,Microbial Sciences Institute, Yale University, West Haven, United States.,Department of Pathology and Laboratory Medicine, McGovern Medical School at University of Texas Health Science Center at Houston, Houston, United States
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50
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Kaplan M, Subramanian P, Ghosal D, Oikonomou CM, Pirbadian S, Starwalt‐Lee R, Mageswaran SK, Ortega DR, Gralnick JA, El‐Naggar MY, Jensen GJ. In situ imaging of the bacterial flagellar motor disassembly and assembly processes. EMBO J 2019; 38:e100957. [PMID: 31304634 PMCID: PMC6627242 DOI: 10.15252/embj.2018100957] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 04/11/2019] [Accepted: 04/18/2019] [Indexed: 11/09/2022] Open
Abstract
The self-assembly of cellular macromolecular machines such as the bacterial flagellar motor requires the spatio-temporal synchronization of gene expression with proper protein localization and association of dozens of protein components. In Salmonella and Escherichia coli, a sequential, outward assembly mechanism has been proposed for the flagellar motor starting from the inner membrane, with the addition of each new component stabilizing the previous one. However, very little is known about flagellar disassembly. Here, using electron cryo-tomography and sub-tomogram averaging of intact Legionella pneumophila, Pseudomonas aeruginosa, and Shewanella oneidensis cells, we study flagellar motor disassembly and assembly in situ. We first show that motor disassembly results in stable outer membrane-embedded sub-complexes. These sub-complexes consist of the periplasmic embellished P- and L-rings, and bend the membrane inward while it remains apparently sealed. Additionally, we also observe various intermediates of the assembly process including an inner-membrane sub-complex consisting of the C-ring, MS-ring, and export apparatus. Finally, we show that the L-ring is responsible for reshaping the outer membrane, a crucial step in the flagellar assembly process.
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Affiliation(s)
- Mohammed Kaplan
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Poorna Subramanian
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Debnath Ghosal
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Catherine M Oikonomou
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Sahand Pirbadian
- Department of Physics and Astronomy, Biological Sciences, and ChemistryUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Ruth Starwalt‐Lee
- BioTechnology InstituteUniversity of Minnesota – Twin CitiesSt. PaulMNUSA
| | | | - Davi R Ortega
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Jeffrey A Gralnick
- BioTechnology InstituteUniversity of Minnesota – Twin CitiesSt. PaulMNUSA
- Department of Plant and Microbial BiologyUniversity of Minnesota – Twin CitiesSt. PaulMNUSA
| | - Mohamed Y El‐Naggar
- Department of Physics and Astronomy, Biological Sciences, and ChemistryUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Grant J Jensen
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
- Howard Hughes Medical InstituteCalifornia Institute of TechnologyPasadenaCAUSA
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