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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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2
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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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3
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Minamino T, Kinoshita M. Structure, Assembly, and Function of Flagella Responsible for Bacterial Locomotion. EcoSal Plus 2023; 11:eesp00112023. [PMID: 37260402 PMCID: PMC10729930 DOI: 10.1128/ecosalplus.esp-0011-2023] [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: 01/18/2023] [Accepted: 04/14/2023] [Indexed: 01/28/2024]
Abstract
Many motile bacteria use flagella for locomotion under a variety of environmental conditions. Because bacterial flagella are under the control of sensory signal transduction pathways, each cell is able to autonomously control its flagellum-driven locomotion and move to an environment favorable for survival. The flagellum of Salmonella enterica serovar Typhimurium is a supramolecular assembly consisting of at least three distinct functional parts: a basal body that acts as a bidirectional rotary motor together with multiple force generators, each of which serves as a transmembrane proton channel to couple the proton flow through the channel with torque generation; a filament that functions as a helical propeller that produces propulsion; and a hook that works as a universal joint that transmits the torque produced by the rotary motor to the helical propeller. At the base of the flagellum is a type III secretion system that transports flagellar structural subunits from the cytoplasm to the distal end of the growing flagellar structure, where assembly takes place. In recent years, high-resolution cryo-electron microscopy (cryoEM) image analysis has revealed the overall structure of the flagellum, and this structural information has made it possible to discuss flagellar assembly and function at the atomic level. In this article, we describe what is known about the structure, assembly, and function of Salmonella flagella.
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Affiliation(s)
- Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Miki Kinoshita
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
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4
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Morimoto YV, Minamino T. Measurements of the Ion Channel Activity of the Transmembrane Stator Complex in the Bacterial Flagellar Motor. Methods Mol Biol 2023; 2646:83-94. [PMID: 36842108 DOI: 10.1007/978-1-0716-3060-0_8] [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] [Indexed: 02/27/2023]
Abstract
The bacterial flagellum is driven by a rotational motor located at the base of the flagellum. The stator unit complex conducts cations such as protons (H+) and sodium ions (Na+) along the electrochemical potential across the cytoplasmic membrane and interacts with the rotor to generate the rotational force. Escherichia coli and Salmonella have the H+-type stator complex, which serves as a transmembrane H+ channel that couples H+ flow through an ion channel to torque generation whereas Vibrio and some Bacillus species have the Na+-type stator complex. In this chapter, we describe how to measure the ion conductivity of the transmembrane stator complex over-expressed in E. coli cells using fluorescent indicators. Intensity measurements of fluorescent indicators using either a fluorescence spectrophotometer or microscope allow quantitative detection of changes in the intracellular ion concentrations due to the ion channel activity of the transmembrane protein complex.
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Affiliation(s)
- Yusuke V Morimoto
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, Fukuoka, Japan.
- Japan Science and Technology Agency, PRESTO, Kawaguchi, Saitama, Japan.
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
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5
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Han Q, Wang SF, Qian XX, Guo L, Shi YF, He R, Yuan JH, Hou YJ, Li DF. Flagellar brake protein YcgR interacts with motor proteins MotA and FliG to regulate the flagellar rotation speed and direction. Front Microbiol 2023; 14:1159974. [PMID: 37125196 PMCID: PMC10140304 DOI: 10.3389/fmicb.2023.1159974] [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: 02/06/2023] [Accepted: 03/24/2023] [Indexed: 05/02/2023] Open
Abstract
In E. coli and related species, flagellar brake protein YcgR responds to the elevated intracellular c-di-GMP, decreases the flagellar rotation speed, causes a CCW rotation bias, and regulates bacterial swimming. Boehm et al. suggested that c-di-GMP-activated YcgR directly interacted with the motor protein MotA to curb flagellar motor output. Paul et al. proposed that YcgR disrupted the organization of the FliG C-terminal domain to bias the flagellar rotation. The target proteins are controversial, and the role of motor proteins remains unclear in flagellar rotation speed and direction regulation by YcgR. Here we assayed the motor proteins' affinity via a modified FRET biosensor and accessed the role of those key residue via bead assays. We found that YcgR could interact with both MotA and FliG, and the affinities could be enhanced upon c-di-GMP binding. Furthermore, residue D54 of YcgR-N was needed for FliG binding. The mutation of the FliG binding residue D54 or the MotA binding ones, F117 and E232, restored flagellar rotation speed in wild-type cells and cells lacking chemotaxis response regulator CheY that switched the flagellar rotation direction and decreased the CCW ratio in wild-type cells. We propose that c-di-GMP-activated YcgR regulated the flagellar rotation speed and direction via its interaction with motor proteins MotA and FliG. Our work suggest the role of YcgR-motor proteins interaction in bacterial swimming regulation.
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Affiliation(s)
- Qun Han
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Shao-Feng Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xin-Xin Qian
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Lu Guo
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yi-Feng Shi
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Rui He
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, China
| | - Jun-Hua Yuan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, China
| | - Yan-Jie Hou
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- *Correspondence: Yan-Jie Hou,
| | - De-Feng Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
- De-Feng Li,
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Hiramatsu Y, Nishida T, Nugraha DK, Osada-Oka M, Nakane D, Imada K, Horiguchi Y. Interference of flagellar rotation up-regulates the expression of small RNA contributing to Bordetella pertussis infection. SCIENCE ADVANCES 2022; 8:eade8971. [PMID: 36542710 PMCID: PMC9770993 DOI: 10.1126/sciadv.ade8971] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 11/18/2022] [Indexed: 06/17/2023]
Abstract
Bacterial small RNAs (sRNAs) posttranscriptionally regulate gene expressions involved in various biological processes, including pathogenicity. Our previous study identified sRNAs, the expression of which was up-regulated in Bordetella pertussis, the causative agent of whooping cough, upon tracheal colonization of the bacteria; however, their roles in bacterial infection remain unknown. Here, we found that one sRNA, Bpr4, contributes to B. pertussis infection by posttranscriptionally up-regulating filamentous hemagglutinin (FHA), a major adhesin of the bacteria. Bpr4 bound to the 5' untranslated region of fhaB mRNA encoding FHA and inhibited its degradation mediated by RNaseE. Our results demonstrated that Bpr4 up-regulation was triggered by the interference of flagellar rotation, which caused the disengagement of MotA, a flagellar stator. Subsequently, MotA activated a diguanylate cyclase to generate cyclic di-GMP, which plays a role in Bpr4 up-regulation through the RisK/RisA two-component system. Our findings indicate that a flagellum-triggered sensory system contributes to B. pertussis infection.
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Affiliation(s)
- Yukihiro Hiramatsu
- Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Takashi Nishida
- Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Dendi Krisna Nugraha
- Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Mayuko Osada-Oka
- Food Hygiene and Environmental Health, Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Shimogamohangi-cho, Sakyo-ku, Kyoto 606-8522, Japan
| | - Daisuke Nakane
- Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan
| | - Katsumi Imada
- Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Yasuhiko Horiguchi
- Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan
- Center for Infectious Disease Education and Research, Osaka University, 2-8 Yamada-oka, Suita, Osaka 565-0871, Japan
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7
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Homma M, Kojima S. The Periplasmic Domain of the Ion-Conducting Stator of Bacterial Flagella Regulates Force Generation. Front Microbiol 2022; 13:869187. [PMID: 35572622 PMCID: PMC9093738 DOI: 10.3389/fmicb.2022.869187] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 03/24/2022] [Indexed: 11/23/2022] Open
Abstract
The bacterial flagellar stator is a unique ion-conducting membrane protein complex composed of two kinds of proteins, the A subunit and the B subunit. The stator couples the ion-motive force across the membrane into rotational force. The stator becomes active only when it is incorporated into the flagellar motor. The periplasmic region of the B subunit positions the stator by using the peptidoglycan-binding (PGB) motif in its periplasmic C-terminal domain to attach to the cell wall. Functional studies based on the crystal structures of the C-terminal domain of the B subunit (MotBC or PomBC) reveal that a dramatic conformational change in a characteristic α-helix allows the stator to conduct ions efficiently and bind to the PG layer. The plug and the following linker region between the transmembrane (TM) and PG-binding domains of the B subunit function in regulating the ion conductance. In Vibrio spp., the transmembrane protein FliL and the periplasmic MotX and MotY proteins also contribute to the motor function. In this review, we describe the functional and structural changes which the stator units undergo to regulate the activity of the stator to drive flagellar rotation.
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Affiliation(s)
- Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
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8
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Takekawa N, Nishikino T, Hori K, Kojima S, Imada K, Homma M. ZomB is essential for chemotaxis of Vibrio alginolyticus by the rotational direction control of the polar flagellar motor. Genes Cells 2021; 26:927-937. [PMID: 34487583 DOI: 10.1111/gtc.12895] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 08/30/2021] [Accepted: 09/01/2021] [Indexed: 11/28/2022]
Abstract
Bacteria exhibit chemotaxis by controlling flagellar rotation to move toward preferred places or away from nonpreferred places. The change in rotation is triggered by the binding of the chemotaxis signaling protein CheY-phosphate (CheY-P) to the C-ring in the flagellar motor. Some specific bacteria, including Vibrio spp. and Shewanella spp., have a single transmembrane protein called ZomB. ZomB is essential for controlling the flagellar rotational direction in Shewanella putrefaciens and Vibrio parahaemolyticus. In this study, we confirmed that the zomB deletion results only in the counterclockwise (CCW) rotation of the motor in Vibrio alginolyticus as previously reported in other bacteria. We found that ZomB is not required for a clockwise-locked phenotype caused by mutations in fliG and fliM, and that ZomB is essential for CW rotation induced by overproduction of CheY-P. Purified ZomB proteins form multimers, suggesting that ZomB may function as a homo-oligomer. These observations imply that ZomB interacts with protein(s) involved in either flagellar motor rotation, chemotaxis, or both. We provide the evidence that ZomB is a new player in chemotaxis and is required for the rotational control in addition to CheY in Vibrio alginolyticus.
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Affiliation(s)
- Norihiro Takekawa
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Tatsuro Nishikino
- Research Center for Next-Generation Protein Sciences, Institute for Protein Research, Osaka University, Suita, Japan
| | - Kiyoshiro Hori
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Katsumi Imada
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
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9
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Pimentel C, Le C, Tuttobene MR, Subils T, Martinez J, Sieira R, Papp-Wallace KM, Keppetipola N, Bonomo RA, Actis LA, Tolmasky ME, Ramirez MS. Human Pleural Fluid and Human Serum Albumin Modulate the Behavior of a Hypervirulent and Multidrug-Resistant (MDR) Acinetobacter baumannii Representative Strain. Pathogens 2021; 10:pathogens10040471. [PMID: 33924559 PMCID: PMC8069197 DOI: 10.3390/pathogens10040471] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 04/09/2021] [Accepted: 04/11/2021] [Indexed: 02/07/2023] Open
Abstract
Acinetobacter baumannii is a nosocomial pathogen capable of causing serious infections associated with high rates of morbidity and mortality. Due to its antimicrobial drug resistance profile, A. baumannii is categorized as an urgent priority pathogen by the Centers for Disease Control and Prevention in the United States and a priority group 1 critical microorganism by the World Health Organization. Understanding how A. baumannii adapts to different host environments may provide critical insights into strategically targeting this pathogen with novel antimicrobial and biological therapeutics. Exposure to human fluids was previously shown to alter the gene expression profile of a highly drug-susceptible A. baumannii strain A118 leading to persistence and survival of this pathogen. Herein, we explore the impact of human pleural fluid (HPF) and human serum albumin (HSA) on the gene expression profile of a highly multi-drug-resistant strain of A. baumannii AB5075. Differential expression was observed for ~30 genes, whose products are involved in quorum sensing, quorum quenching, iron acquisition, fatty acid metabolism, biofilm formation, secretion systems, and type IV pilus formation. Phenotypic and further transcriptomic analysis using quantitative RT-PCR confirmed RNA-seq data and demonstrated a distinctive role of HSA as the molecule involved in A. baumannii’s response.
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Affiliation(s)
- Camila Pimentel
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831-3599, USA; (C.P.); (C.L.); (M.R.T.); (J.M.); (M.E.T.)
| | - Casin Le
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831-3599, USA; (C.P.); (C.L.); (M.R.T.); (J.M.); (M.E.T.)
| | - Marisel R. Tuttobene
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831-3599, USA; (C.P.); (C.L.); (M.R.T.); (J.M.); (M.E.T.)
| | - Tomas Subils
- Instituto de Procesos Biotecnológicos y Químicos de Rosario (IPROBYQ, CONICET-UNR), Rosario S2002LRK, Argentina;
| | - Jasmine Martinez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831-3599, USA; (C.P.); (C.L.); (M.R.T.); (J.M.); (M.E.T.)
| | - Rodrigo Sieira
- Fundación Instituto Leloir—IIBBA CONICET, Buenos Aires C1405BWE, Argentina;
| | - Krisztina M. Papp-Wallace
- Research Service and GRECC, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA; (K.M.P.-W.); (R.A.B.)
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH 44106, USA
| | - Niroshika Keppetipola
- Department of Chemistry and Biochemistry, California State University Fullerton, Fullerton, CA 92831-3599, USA;
| | - Robert A. Bonomo
- Research Service and GRECC, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA; (K.M.P.-W.); (R.A.B.)
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH 44106, USA
| | - Luis A. Actis
- Department of Microbiology, Miami University, Oxford, OH 45056, USA;
| | - Marcelo E. Tolmasky
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831-3599, USA; (C.P.); (C.L.); (M.R.T.); (J.M.); (M.E.T.)
| | - Maria Soledad Ramirez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831-3599, USA; (C.P.); (C.L.); (M.R.T.); (J.M.); (M.E.T.)
- Correspondence: ; Tel.: +1-657-278-4562
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10
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Site-directed crosslinking identifies the stator-rotor interaction surfaces in a hybrid bacterial flagellar motor. J Bacteriol 2021; 203:JB.00016-21. [PMID: 33619152 PMCID: PMC8092157 DOI: 10.1128/jb.00016-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The bacterial flagellum is the motility organelle powered by a rotary motor. The rotor and stator elements of the motor are located in the cytoplasmic membrane and cytoplasm. The stator units assemble around the rotor, and an ion flux (typically H+ or Na+) conducted through a channel of the stator induces conformational changes that generate rotor torque. Electrostatic interactions between the stator protein PomA in Vibrio (MotA in Escherichia coli) and the rotor protein FliG have been shown by genetic analyses, but have not been demonstrated biochemically. Here, we used site-directed photo- and disulfide-crosslinking to provide direct evidence for the interaction. We introduced a UV-reactive amino acid, p-benzoyl-L-phenylalanine (pBPA), into the cytoplasmic region of PomA or the C-terminal region of FliG in intact cells. After UV irradiation, pBPA inserted at a number of positions in PomA formed a crosslink with FliG. PomA residue K89 gave the highest yield of crosslinks, suggesting that it is the PomA residue nearest to FliG. UV-induced crosslinking stopped motor rotation, and the isolated hook-basal body contained the crosslinked products. pBPA inserted to replace residues R281 or D288 in FliG formed crosslinks with the Escherichia coli stator protein, MotA. A cysteine residue introduced in place of PomA K89 formed disulfide crosslinks with cysteine inserted in place of FliG residues R281 and D288, and some other flanking positions. These results provide the first demonstration of direct physical interaction between specific residues in FliG and PomA/MotA.ImportanceThe bacterial flagellum is a unique organelle that functions as a rotary motor. The interaction between the stator and rotor is indispensable for stator assembly into the motor and the generation of motor torque. However, the interface of the stator-rotor interaction has only been defined by mutational analysis. Here, we detected the stator-rotor interaction using site-directed photo- and disulfide-crosslinking approaches. We identified several residues in the PomA stator, especially K89, that are in close proximity to the rotor. Moreover, we identified several pairs of stator and rotor residues that interact. This study directly demonstrates the nature of the stator-rotor interaction and suggests how stator units assemble around the rotor and generate torque in the bacterial flagellar motor.
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11
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Morimoto YV, Minamino T. Architecture and Assembly of the Bacterial Flagellar Motor Complex. Subcell Biochem 2021; 96:297-321. [PMID: 33252734 DOI: 10.1007/978-3-030-58971-4_8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
One of the central systems responsible for bacterial motility is the flagellum. The bacterial flagellum is a macromolecular protein complex that is more than five times the cell length. Flagella-driven motility is coordinated via a chemosensory signal transduction pathway, and so bacterial cells sense changes in the environment and migrate towards more desirable locations. The flagellum of Salmonella enterica serovar Typhimurium is composed of a bi-directional rotary motor, a universal joint and a helical propeller. The flagellar motor, which structurally resembles an artificial motor, is embedded within the cell envelop and spins at several hundred revolutions per second. In contrast to an artificial motor, the energy utilized for high-speed flagellar motor rotation is the inward-directed proton flow through a transmembrane proton channel of the stator unit of the flagellar motor. The flagellar motor realizes efficient chemotaxis while performing high-speed movement by an ingenious directional switching mechanism of the motor rotation. To build the universal joint and helical propeller structures outside the cell body, the flagellar motor contains its own protein transporter called a type III protein export apparatus. In this chapter we summarize the structure and assembly of the Salmonella flagellar motor complex.
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Affiliation(s)
- Yusuke V Morimoto
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502, Japan
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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12
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Guan G, Zhang L, Zhu J, Wu H, Li W, Sun Q. Antibacterial properties and mechanism of biopolymer-based films functionalized by CuO/ZnO nanoparticles against Escherichia coli and Staphylococcus aureus. JOURNAL OF HAZARDOUS MATERIALS 2021; 402:123542. [PMID: 32745874 DOI: 10.1016/j.jhazmat.2020.123542] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/10/2020] [Accepted: 07/21/2020] [Indexed: 06/11/2023]
Abstract
In this study, the nanocomposite film (SA-CS@CuO/ZnO) composed of sodium alginate (SA) and chitosan (CS) functionalized by copper oxide nanoparticles (CuONPs) and zinc oxide nanoparticles (ZnONPs) was fabricated, then its antibacterial mechanisms against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were systematically investigated. When the contents of CuONPs and ZnONPs reached 1.5 % (w/w) and 0.5 % (w/w), respectively, the SA-CS@CuO/ZnO exhibited great mechanical, barrier, and optical properties. Moreover, the incorporation of ZnONPs enhanced the photocatalytic ability of SA-CS@CuO/ZnO, producing a high level of reactive oxygen species under light irradiation. Further, antibacterial results showed that SA-CS@CuO/ZnO treatment inhibited the growth of E. coli and S. aureus higher than 60 % in the dark and exceeded 90 % under light irradiation. This was also manifested in the incompleteness of bacterial cell structure, accompanied by unstable cellular redox balance and DNA disruption. The functions of differentially expressed genes screened by transcriptome analysis were mainly involved in membrane transport, cell wall and membrane synthesis, cellular antioxidant defense system, cell membrane and DNA repair system. The changes in bacterial transcriptional regulation reflected the disturbance in the physiological activities and loss of cell integrity, leading to damage of bacterial cells or death.
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Affiliation(s)
- Guilin Guan
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, Shandong, People's Republic of China
| | - Linan Zhang
- College of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, Shandong, People's Republic of China
| | - Junxiang Zhu
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, Shandong, People's Republic of China
| | - Hao Wu
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, Shandong, People's Republic of China.
| | - Wenxiang Li
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, Shandong, People's Republic of China
| | - Qingjie Sun
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, Shandong, People's Republic of China
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13
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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: 5.3] [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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14
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Morimoto YV, Namba K, Minamino T. GFP Fusion to the N-Terminus of MotB Affects the Proton Channel Activity of the Bacterial Flagellar Motor in Salmonella. Biomolecules 2020; 10:E1255. [PMID: 32872412 PMCID: PMC7564593 DOI: 10.3390/biom10091255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/25/2020] [Accepted: 08/27/2020] [Indexed: 12/28/2022] Open
Abstract
The bacterial flagellar motor converts the energy of proton flow through the MotA/MotB complex into mechanical works required for motor rotation. The rotational force is generated by electrostatic interactions between the stator protein MotA and the rotor protein FliG. The Arg-90 and Glu-98 from MotA interact with Asp-289 and Arg-281 of FliG, respectively. An increase in the expression level of the wild-type MotA/MotB complex inhibits motility of the gfp-motBfliG(R281V) mutant but not the fliG(R281V) mutant, suggesting that the MotA/GFP-MotB complex cannot work together with wild-type MotA/MotB in the presence of the fliG(R281V) mutation. However, it remains unknown why. Here, we investigated the effect of the GFP fusion to MotB at its N-terminus on the MotA/MotB function. Over-expression of wild-type MotA/MotB significantly reduced the growth rate of the gfp-motBfliG(R281V) mutant. The over-expression of the MotA/GFP-MotB complex caused an excessive proton leakage through its proton channel, thereby inhibiting cell growth. These results suggest that the GFP tag on the MotB N-terminus affects well-regulated proton translocation through the MotA/MotB proton channel. Therefore, we propose that the N-terminal cytoplasmic tail of MotB couples the gating of the proton channel with the MotA-FliG interaction responsible for torque generation.
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Affiliation(s)
- Yusuke V. Morimoto
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka 820-8502, Japan
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan; (K.N.); (T.M.)
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan; (K.N.); (T.M.)
- RIKEN Spring-8 Center & Center for Biosystems Dynamics Research (BDR), 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
- JEOL YOKOGUSHI Research Alliance Laboratories, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan; (K.N.); (T.M.)
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15
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Johnson S, Fong YH, Deme JC, Furlong EJ, Kuhlen L, Lea SM. Symmetry mismatch in the MS-ring of the bacterial flagellar rotor explains the structural coordination of secretion and rotation. Nat Microbiol 2020; 5:966-975. [PMID: 32284565 PMCID: PMC7320910 DOI: 10.1038/s41564-020-0703-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 03/05/2020] [Indexed: 11/14/2022]
Abstract
The bacterial flagellum is a complex self-assembling nanomachine that confers motility to the cell. Despite great variation across species, all flagella are ultimately constructed from a helical propeller that is attached to a motor embedded in the inner membrane. The motor consists of a series of stator units surrounding a central rotor made up of two ring complexes, the MS-ring and the C-ring. Despite many studies, high-resolution structural information is still lacking for the MS-ring of the rotor, and proposed mismatches in stoichiometry between the two rings have long provided a source of confusion for the field. Here, we present structures of the Salmonella MS-ring, revealing a high level of variation in inter- and intrachain symmetry that provides a structural explanation for the ability of the MS-ring to function as a complex and elegant interface between the two main functions of the flagellum-protein secretion and rotation.
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Affiliation(s)
- Steven Johnson
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Yu Hang Fong
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Justin C Deme
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- Central Oxford Structural Molecular Imaging Centre, University of Oxford, Oxford, UK
| | - Emily J Furlong
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Lucas Kuhlen
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Susan M Lea
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
- Central Oxford Structural Molecular Imaging Centre, University of Oxford, Oxford, UK.
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16
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Khan S. The Architectural Dynamics of the Bacterial Flagellar Motor Switch. Biomolecules 2020; 10:E833. [PMID: 32486003 PMCID: PMC7355467 DOI: 10.3390/biom10060833] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/23/2020] [Accepted: 05/25/2020] [Indexed: 02/06/2023] Open
Abstract
The rotary bacterial flagellar motor is remarkable in biochemistry for its highly synchronized operation and amplification during switching of rotation sense. The motor is part of the flagellar basal body, a complex multi-protein assembly. Sensory and energy transduction depends on a core of six proteins that are adapted in different species to adjust torque and produce diverse switches. Motor response to chemotactic and environmental stimuli is driven by interactions of the core with small signal proteins. The initial protein interactions are propagated across a multi-subunit cytoplasmic ring to switch torque. Torque reversal triggers structural transitions in the flagellar filament to change motile behavior. Subtle variations in the core components invert or block switch operation. The mechanics of the flagellar switch have been studied with multiple approaches, from protein dynamics to single molecule and cell biophysics. The architecture, driven by recent advances in electron cryo-microscopy, is available for several species. Computational methods have correlated structure with genetic and biochemical databases. The design principles underlying the basis of switch ultra-sensitivity and its dependence on motor torque remain elusive, but tantalizing clues have emerged. This review aims to consolidate recent knowledge into a unified platform that can inspire new research strategies.
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Affiliation(s)
- Shahid Khan
- Molecular Biology Consortium, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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17
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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: 5] [Impact Index Per Article: 1.3] [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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18
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Ma GL, Chandra H, Liang ZX. Taming the flagellar motor of pseudomonads with a nucleotide messenger. Environ Microbiol 2020; 22:2496-2513. [PMID: 32329141 DOI: 10.1111/1462-2920.15036] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 01/11/2023]
Abstract
Pseudomonads rely on the flagellar motor to rotate a polar flagellum for swimming and swarming, and to sense surfaces for initiating the motile-to-sessile transition to adopt a surface-dwelling lifestyle. Deciphering the function and regulation of the flagellar motor is of paramount importance for understanding the behaviours of environmental and pathogenic pseudomonads. Recent studies disclosed the preeminent role played by the messenger c-di-GMP in controlling the real-time performance of the flagellar motor in pseudomonads. The studies revealed that c-di-GMP controls the dynamic exchange of flagellar stator units to regulate motor torque/speed and modulates the frequency of flagellar motor switching via the chemosensory signalling pathways. Apart from being a rotary motor, the flagellar motor is emerging as a mechanosensor that transduces surface-induced mechanical signals into an increase of cellular c-di-GMP concentration to initiate the cellular programs required for long-term colonization. Collectively, the studies generate long-awaited mechanistic insights into how c-di-GMP regulates bacterial motility and the motile-to-sessile transition. The new findings also raise the fundamental questions of how cellular c-di-GMP concentrations are dynamically coupled to flagellar output and the proton-motive force, and how c-di-GMP signalling is coordinated spatiotemporally to fine-tune flagellar response and the behaviour of pseudomonads in solutions and on surfaces.
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Affiliation(s)
- Guang-Lei Ma
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore
| | - Hartono Chandra
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore
| | - Zhao-Xun Liang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore.,Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore
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19
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Nord AL, Pedaci F. Mechanisms and Dynamics of the Bacterial Flagellar Motor. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1267:81-100. [PMID: 32894478 DOI: 10.1007/978-3-030-46886-6_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Many bacteria are able to actively propel themselves through their complex environment, in search of resources and suitable niches. The source of this propulsion is the Bacterial Flagellar Motor (BFM), a molecular complex embedded in the bacterial membrane which rotates a flagellum. In this chapter we review the known physical mechanisms at work in the motor. The BFM shows a highly dynamic behavior in its power output, its structure, and in the stoichiometry of its components. Changes in speed, rotation direction, constituent protein conformations, and the number of constituent subunits are dynamically controlled in accordance to external chemical and mechanical cues. The mechano-sensitivity of the motor is likely related to the surface-sensing ability of bacteria, relevant in the initial stage of biofilm formation.
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Affiliation(s)
- A L Nord
- Centre de Biochimie Structurale (CBS), INSERM, CNRS, University of Montpellier, Montpellier, France
| | - F Pedaci
- Centre de Biochimie Structurale (CBS), INSERM, CNRS, University of Montpellier, Montpellier, France.
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20
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Nakamura S, Hanaizumi Y, Morimoto YV, Inoue Y, Erhardt M, Minamino T, Namba K. Direct observation of speed fluctuations of flagellar motor rotation at extremely low load close to zero. Mol Microbiol 2019; 113:755-765. [DOI: 10.1111/mmi.14440] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 12/10/2019] [Accepted: 12/10/2019] [Indexed: 12/22/2022]
Affiliation(s)
- Shuichi Nakamura
- Department of Applied Physics, Graduate School of Engineering Tohoku University Sendai Japan
| | - Yuta Hanaizumi
- Department of Applied Physics, Graduate School of Engineering Tohoku University Sendai Japan
| | - Yusuke V. Morimoto
- Faculty of Computer Science and Systems Engineering, Department of Physics and Information Technology Kyushu Institute of Technology Fukuoka Japan
| | - Yumi Inoue
- Graduate School of Frontier Biosciences Osaka University Osaka Japan
| | - Marc Erhardt
- Institut für Biologie/Bakterienphysiologie Humboldt‐Universität zu Berlin Berlin Germany
| | - Tohru Minamino
- Graduate School of Frontier Biosciences Osaka University Osaka Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences Osaka University Osaka Japan
- RIKEN Spring‐8 Center and Center for Biosystems Dynamics Research Osaka Japan
- JEOL YOKOGUSHI Research Alliance Laboratories Osaka University Osaka Japan
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21
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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: 1.6] [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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22
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Abstract
The bacterial flagellum is a reversible rotating motor powered by ion transport through stator units, which also exert torque on the rotor component to turn the flagellum for motility. Species-specific adaptations to flagellar motors impact stator function to meet the demands of each species to sufficiently power flagellar rotation. We identified another evolutionary adaptation by discovering that FlgX of Campylobacter jejuni preserves the integrity of stator units by functioning as a chaperone to protect stator proteins from degradation by the FtsH protease complex due to the physiology of the bacterium. FlgX is required to maintain a level of stator units sufficient to power the naturally high-torque flagellar motor of C. jejuni for motility in intestinal mucosal layers to colonize hosts. Our work continues to identify an increasing number of adaptations to flagellar motors across bacterial species that provide the mechanics necessary for producing an effective rotating nanomachine for motility. The stator units of the flagellum supply power to the flagellar motor via ion transport across the cytoplasmic membrane and generate torque on the rotor for rotation. Flagellar motors across bacterial species have evolved adaptations that impact and enhance stator function to meet the demands of each species, including producing stator units using different fuel types or various stator units for different motility modalities. Campylobacter jejuni produces one of the most complex and powerful flagellar motors by positioning 17 stator units at a greater radial distance than in most other bacteria to increase power and torque for high velocity of motility. We report another evolutionary adaptation impacting flagellar stators by identifying FlgX as a chaperone for C. jejuni stator units to ensure sufficient power and torque for flagellar rotation and motility. We discovered that FlgX maintains MotA and MotB stator protein integrity likely through a direct interaction with MotA that prevents their degradation. Suppressor analysis suggested that the physiology of C. jejuni drives the requirement for FlgX to protect stator units from proteolysis by the FtsH protease complex. C. jejuni ΔflgX was strongly attenuated for colonization of the natural avian host, but colonization capacity was greatly restored by a single mutation in MotA. These findings suggest that the likely sole function of FlgX is to preserve stator unit integrity for the motility required for host interactions. Our findings demonstrate another evolved adaptation in motile bacteria to ensure the equipment of the flagellar motor with sufficient power to generate torque for motility.
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23
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Minamino T, Kinoshita M, Namba K. Directional Switching Mechanism of the Bacterial Flagellar Motor. Comput Struct Biotechnol J 2019; 17:1075-1081. [PMID: 31452860 PMCID: PMC6700473 DOI: 10.1016/j.csbj.2019.07.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/26/2019] [Accepted: 07/27/2019] [Indexed: 11/16/2022] Open
Abstract
Bacteria sense temporal changes in extracellular stimuli via sensory signal transducers and move by rotating flagella towards into a favorable environment for their survival. Each flagellum is a supramolecular motility machine consisting of a bi-directional rotary motor, a universal joint and a helical propeller. The signal transducers transmit environmental signals to the flagellar motor through a cytoplasmic chemotactic signaling pathway. The flagellar motor is composed of a rotor and multiple stator units, each of which acts as a transmembrane proton channel to conduct protons and exert force on the rotor. FliG, FliM and FliN form the C ring on the cytoplasmic face of the basal body MS ring made of the transmembrane protein FliF and act as the rotor. The C ring also serves as a switching device that enables the motor to spin in both counterclockwise (CCW) and clockwise (CW) directions. The phosphorylated form of the chemotactic signaling protein CheY binds to FliM and FliN to induce conformational changes of the C ring responsible for switching the direction of flagellar motor rotation from CCW to CW. In this mini-review, we will describe current understanding of the switching mechanism of the bacterial flagellar motor.
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Affiliation(s)
- Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadoaka, Suita, Osaka 565-0871, Japan
| | - Miki Kinoshita
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadoaka, Suita, Osaka 565-0871, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadoaka, Suita, Osaka 565-0871, Japan
- RIKEN Center for Biosystems Dynamic Research & Spring-8 Center, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
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24
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Flagella-Driven Motility of Bacteria. Biomolecules 2019; 9:biom9070279. [PMID: 31337100 PMCID: PMC6680979 DOI: 10.3390/biom9070279] [Citation(s) in RCA: 181] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 07/11/2019] [Accepted: 07/12/2019] [Indexed: 01/17/2023] Open
Abstract
The bacterial flagellum is a helical filamentous organelle responsible for motility. In bacterial species possessing flagella at the cell exterior, the long helical flagellar filament acts as a molecular screw to generate thrust. Meanwhile, the flagella of spirochetes reside within the periplasmic space and not only act as a cytoskeleton to determine the helicity of the cell body, but also rotate or undulate the helical cell body for propulsion. Despite structural diversity of the flagella among bacterial species, flagellated bacteria share a common rotary nanomachine, namely the flagellar motor, which is located at the base of the filament. The flagellar motor is composed of a rotor ring complex and multiple transmembrane stator units and converts the ion flux through an ion channel of each stator unit into the mechanical work required for motor rotation. Intracellular chemotactic signaling pathways regulate the direction of flagella-driven motility in response to changes in the environments, allowing bacteria to migrate towards more desirable environments for their survival. Recent experimental and theoretical studies have been deepening our understanding of the molecular mechanisms of the flagellar motor. In this review article, we describe the current understanding of the structure and dynamics of the bacterial flagellum.
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25
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Abstract
Bacteria move by a variety of mechanisms, but the best understood types of motility are powered by flagella (72). Flagella are complex machines embedded in the cell envelope that rotate a long extracellular helical filament like a propeller to push cells through the environment. The flagellum is one of relatively few biological machines that experience continuous 360° rotation, and it is driven by one of the most powerful motors, relative to its size, on earth. The rotational force (torque) generated at the base of the flagellum is essential for motility, niche colonization, and pathogenesis. This review describes regulatory proteins that control motility at the level of torque generation.
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Affiliation(s)
- Sundharraman Subramanian
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA.,Biochemistry Graduate Program, Indiana University, Bloomington, Indiana 47405, USA
| | - Daniel B Kearns
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA;
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26
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Sakai T, Miyata T, Terahara N, Mori K, Inoue Y, Morimoto YV, Kato T, Namba K, Minamino T. Novel Insights into Conformational Rearrangements of the Bacterial Flagellar Switch Complex. mBio 2019; 10:e00079-19. [PMID: 30940700 PMCID: PMC6445934 DOI: 10.1128/mbio.00079-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 02/26/2019] [Indexed: 01/01/2023] Open
Abstract
The flagellar motor can spin in both counterclockwise (CCW) and clockwise (CW) directions. The flagellar motor consists of a rotor and multiple stator units, which act as a proton channel. The rotor is composed of the transmembrane MS ring made of FliF and the cytoplasmic C ring consisting of FliG, FliM, and FliN. The C ring is directly involved in rotation and directional switching. The Salmonella FliF-FliG deletion fusion motor missing 56 residues from the C terminus of FliF and 94 residues from the N terminus of FliG keeps a domain responsible for the interaction with the stator intact, but its motor function is reduced significantly. Here, we report the structure and function of the FliF-FliG deletion fusion motor. The FliF-FliG deletion fusion not only resulted in a strong CW switch bias but also affected rotor-stator interactions coupled with proton translocation through the proton channel of the stator unit. The energy coupling efficiency of the deletion fusion motor was the same as that of the wild-type motor. Extragenic suppressor mutations in FliG, FliM, or FliN not only relieved the strong CW switch bias but also increased the motor speed at low load. The FliF-FliG deletion fusion made intersubunit interactions between C ring proteins tighter compared to the wild-type motor, whereas the suppressor mutations affect such tighter intersubunit interactions. We propose that a change of intersubunit interactions between the C ring proteins may be required for high-speed motor rotation as well as direction switching.IMPORTANCE The bacterial flagellar motor is a bidirectional rotary motor for motility and chemotaxis, which often plays an important role in infection. The motor is a large transmembrane protein complex composed of a rotor and multiple stator units, which also act as a proton channel. Motor torque is generated through their cyclic association and dissociation coupled with proton translocation through the proton channel. A large cytoplasmic ring of the motor, called C ring, is responsible for rotation and switching by interacting with the stator, but the mechanism remains unknown. By analyzing the structure and function of the wild-type motor and a mutant motor missing part of the C ring connecting itself with the transmembrane rotor ring while keeping a stator-interacting domain for bidirectional torque generation intact, we found interesting clues to the change in the C ring conformation for the switching and rotation involving loose and tight intersubunit interactions.
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Affiliation(s)
- Tomofumi Sakai
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Tomoko Miyata
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Naoya Terahara
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Koichiro Mori
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Yumi Inoue
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Yusuke V Morimoto
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
- RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
- Department of Bioscience and Bioinformatics, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, Fukuoka, Japan
| | - Takayuki Kato
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
- RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
- RIKEN SPring-8 Center, Suita, Osaka, Japan
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
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Chelliah R, Wei S, Park BJ, Rubab M, Banan-Mwine Dalirii E, Barathikannan K, Jin YG, Oh DH. Whole genome sequence of Bacillus thuringiensis ATCC 10792 and improved discrimination of Bacillus thuringiensis from Bacillus cereus group based on novel biomarkers. Microb Pathog 2019; 129:284-297. [DOI: 10.1016/j.micpath.2019.02.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 02/08/2019] [Accepted: 02/08/2019] [Indexed: 11/17/2022]
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Zhang J, Wang X, Suo X, Liu X, Liu B, Yuan M, Wang G, Liang C, Shi H. Cellular Response of Escherichia coli to Photocatalysis: Flagellar Assembly Variation and Beyond. ACS NANO 2019; 13:2004-2014. [PMID: 30721027 DOI: 10.1021/acsnano.8b08475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Bacterial cells can be inactivated by external reactive oxygen species (ROS) produced by semiconductor photocatalysis. However, little is known about cellular responses to photocatalysis. For a better understanding of this issue, one strain of Escherichia coli ( E. coli, hereafter named as MT), which has an increased ability to metabolize carbon sources, was screened out from the wild-type (WT) E. coli K12 by repeated exposure to photocatalysis with palladium oxide modified nitrogen-doped titanium dioxide. In this study, transcriptome sequencing of the WT and MT strains that were exposed or unexposed to photocatalysis were carried out. Cellular responses to photocatalysis were inferred from the functions of genes whose transcripts were either increased or decreased. Upregulation of expression of bacterial flagellar assembly genes used for chemotaxis was detected in cells exposed to semilethal photocatalytic conditions of the WT E. coli. Increased capability to degrade superoxide radicals and decreased bacterial flagellar assembly and chemotaxis were observed in MT E. coli compared to WT cells. We conclude that the differences in motility and intracellular ROS between MT and WT are directly related to survivability of E. coli during exposure to photodisinfection.
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Affiliation(s)
- Jingtao Zhang
- Collaborative Innovation Centre of Food Production and Safety, Henan Key Laboratory of Cold Chain Food Quality and Safety Control, School of Food and Bioengineering , Zhengzhou University of Light Industry , Zhengzhou 450002 , China
| | - Xueying Wang
- Collaborative Innovation Centre of Food Production and Safety, Henan Key Laboratory of Cold Chain Food Quality and Safety Control, School of Food and Bioengineering , Zhengzhou University of Light Industry , Zhengzhou 450002 , China
| | - Xinying Suo
- Collaborative Innovation Centre of Food Production and Safety, Henan Key Laboratory of Cold Chain Food Quality and Safety Control, School of Food and Bioengineering , Zhengzhou University of Light Industry , Zhengzhou 450002 , China
| | - Xing Liu
- Collaborative Innovation Centre of Food Production and Safety, Henan Key Laboratory of Cold Chain Food Quality and Safety Control, School of Food and Bioengineering , Zhengzhou University of Light Industry , Zhengzhou 450002 , China
| | - Bingkun Liu
- School of Material and Chemical Engineering , Zhengzhou University of Light Industry , Zhengzhou 450002 , China
| | - Mingming Yuan
- Collaborative Innovation Centre of Food Production and Safety, Henan Key Laboratory of Cold Chain Food Quality and Safety Control, School of Food and Bioengineering , Zhengzhou University of Light Industry , Zhengzhou 450002 , China
| | - Guanglu Wang
- Collaborative Innovation Centre of Food Production and Safety, Henan Key Laboratory of Cold Chain Food Quality and Safety Control, School of Food and Bioengineering , Zhengzhou University of Light Industry , Zhengzhou 450002 , China
| | - Chengzhen Liang
- Biotechnology Research Institute , Chinese Academy of Agricultural Sciences , Beijing 100081 , China
| | - Hengzhen Shi
- School of Material and Chemical Engineering , Zhengzhou University of Light Industry , Zhengzhou 450002 , China
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29
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Effect of the MotA(M206I) Mutation on Torque Generation and Stator Assembly in the Salmonella H +-Driven Flagellar Motor. J Bacteriol 2019; 201:JB.00727-18. [PMID: 30642987 DOI: 10.1128/jb.00727-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 01/03/2019] [Indexed: 12/20/2022] Open
Abstract
The bacterial flagellar motor is composed of a rotor and a dozen stators and converts the ion flux through the stator into torque. Each stator unit alternates in its attachment to and detachment from the rotor even during rotation. In some species, stator assembly depends on the input energy, but it remains unclear how an electrochemical potential across the membrane (e.g., proton motive force [PMF]) or ion flux is involved in stator assembly dynamics. Here, we focused on pH dependence of a slow motile MotA(M206I) mutant of Salmonella The MotA(M206I) motor produces torque comparable to that of the wild-type motor near stall, but its rotation rate is considerably decreased as the external load is reduced. Rotation assays of flagella labeled with 1-μm beads showed that the rotation rate of the MotA(M206I) motor is increased by lowering the external pH whereas that of the wild-type motor is not. Measurements of the speed produced by a single stator unit using 1-μm beads showed that the unit speed of the MotA(M206I) is about 60% of that of the wild-type and that a decrease in external pH did not affect the MotA(M206I) unit speed. Analysis of the subcellular stator localization revealed that the number of functional stators is restored by lowering the external pH. The pH-dependent improvement of stator assembly was observed even when the PMF was collapsed and proton transfer was inhibited. These results suggest that MotA-Met206 is responsible for not only load-dependent energy coupling between the proton influx and rotation but also pH-dependent stator assembly.IMPORTANCE The bacterial flagellar motor is a rotary nanomachine driven by the electrochemical transmembrane potential (ion motive force). About 10 stators (MotA/MotB complexes) are docked around a rotor, and the stator recruitment depends on the load, ion motive force, and coupling ion flux. The MotA(M206I) mutation slows motor rotation and decreases the number of docked stators in Salmonella We show that lowering the external pH improves the assembly of the mutant stators. Neither the collapse of the ion motive force nor a mutation mimicking the proton-binding state inhibited stator localization to the motor. These results suggest that MotA-Met206 is involved in torque generation and proton translocation and that stator assembly is stabilized by protonation of the stator.
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Abstract
Bacteria, life living at microscale, can spread only by thermal fluctuation. However, the ability of directional movement, such as swimming by rotating flagella, gliding over surfaces via mobile cell-surface adhesins, and actin-dependent movement, could be useful for thriving through searching more favorable environments, and such motility is known to be related to pathogenicity. Among diverse migration mechanisms, perhaps flagella-dependent motility would be used by most species. The bacterial flagellum is a molecular nanomachine comprising a helical filament and a basal motor, which is fueled by an electrochemical gradient of cation across the cell membrane (ion motive force). Many species, such as Escherichia coli, possess flagella on the outside of the cell body, whereas flagella of spirochetes reside within the periplasmic space. Flagellar filaments or helical spirochete bodies rotate like a screw propeller, generating propulsive force. This review article describes the current knowledge of the structure and operation mechanism of the bacterial flagellum, and flagella-dependent motility in highly viscous environments.
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Affiliation(s)
- Shuichi Nakamura
- Department of Applied Physics, Graduate School of Engineering, Tohoku University
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31
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Minamino T, Terahara N, Kojima S, Namba K. Autonomous control mechanism of stator assembly in the bacterial flagellar motor in response to changes in the environment. Mol Microbiol 2018; 109:723-734. [DOI: 10.1111/mmi.14092] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/26/2018] [Accepted: 07/28/2018] [Indexed: 01/02/2023]
Affiliation(s)
- Tohru Minamino
- Graduate School of Frontier Biosciences Osaka University 1‐3 YamadaokaSuita Osaka 565‐0871Japan
| | - Naoya Terahara
- Graduate School of Frontier Biosciences Osaka University 1‐3 YamadaokaSuita Osaka 565‐0871Japan
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science Nagoya University Chikusa‐kuNagoya 464‐8602Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences Osaka University 1‐3 YamadaokaSuita Osaka 565‐0871Japan
- RIKEN Center for Biosystems Dynamics Research & SPring‐8 Center 1‐3 YamadaokaSuita Osaka 565‐0871Japan
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32
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Bacterial flagellar switching: a molecular mechanism directed by the logic of an electric motor. J Mol Model 2018; 24:280. [DOI: 10.1007/s00894-018-3819-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 08/30/2018] [Indexed: 11/27/2022]
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33
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Suo Y, Gao S, Baranzoni GM, Xie Y, Liu Y. Comparative transcriptome RNA-Seq analysis of Listeria monocytogenes with sodium lactate adaptation. Food Control 2018. [DOI: 10.1016/j.foodcont.2018.03.044] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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34
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Máté de Gérando H, Wasels F, Bisson A, Clement B, Bidard F, Jourdier E, López-Contreras AM, Lopes Ferreira N. Genome and transcriptome of the natural isopropanol producer Clostridium beijerinckii DSM6423. BMC Genomics 2018; 19:242. [PMID: 29636009 PMCID: PMC5894183 DOI: 10.1186/s12864-018-4636-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 03/28/2018] [Indexed: 12/23/2022] Open
Abstract
Background There is a worldwide interest for sustainable and environmentally-friendly ways to produce fuels and chemicals from renewable resources. Among them, the production of acetone, butanol and ethanol (ABE) or Isopropanol, Butanol and Ethanol (IBE) by anaerobic fermentation has already a long industrial history. Isopropanol has recently received a specific interest and the best studied natural isopropanol producer is C. beijerinckii DSM 6423 (NRRL B-593). This strain metabolizes sugars into a mix of IBE with only low concentrations of ethanol produced (< 1 g/L). However, despite its relative ancient discovery, few genomic details have been described for this strain. Research efforts including omics and genetic engineering approaches are therefore needed to enable the use of C. beijerinckii as a microbial cell factory for production of isopropanol. Results The complete genome sequence and a first transcriptome analysis of C. beijerinckii DSM 6423 are described in this manuscript. The combination of MiSeq and de novo PacBio sequencing revealed a 6.38 Mbp chromosome containing 6254 genomic objects. Three Mobile Genetic Elements (MGE) were also detected: a linear double stranded DNA bacteriophage (ϕ6423) and two plasmids (pNF1 and pNF2) highlighting the genomic complexity of this strain. A first RNA-seq transcriptomic study was then performed on 3 independent glucose fermentations. Clustering analysis allowed us to detect some key gene clusters involved in the main life cycle steps (acidogenesis, solvantogenesis and sporulation) and differentially regulated among the fermentation. These putative clusters included some putative metabolic operons comparable to those found in other reference strains such as C. beijerinckii NCIMB 8052 or C. acetobutylicum ATCC 824. Interestingly, only one gene was encoding for an alcohol dehydrogenase converting acetone into isopropanol, suggesting a single genomic event occurred on this strain to produce isopropanol. Conclusions We present the full genome sequence of Clostridium beijerinckii DSM 6423, providing a complete genetic background of this strain. This offer a great opportunity for the development of dedicated genetic tools currently lacking for this strain. Moreover, a first RNA-seq analysis allow us to better understand the global metabolism of this natural isopropanol producer, opening the door to future targeted engineering approaches. Electronic supplementary material The online version of this article (10.1186/s12864-018-4636-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hadrien Máté de Gérando
- Wageningen Food and Biobased Research, Bornse Weilanden 9, 6709WG, Wageningen, The Netherlands.,IFP Energies Nouvelles, 1 et 4 avenue de Bois-Préau, 92852, Rueil-Malmaison, France
| | - François Wasels
- IFP Energies Nouvelles, 1 et 4 avenue de Bois-Préau, 92852, Rueil-Malmaison, France
| | - Angélique Bisson
- IFP Energies Nouvelles, 1 et 4 avenue de Bois-Préau, 92852, Rueil-Malmaison, France
| | - Benjamin Clement
- IFP Energies Nouvelles, 1 et 4 avenue de Bois-Préau, 92852, Rueil-Malmaison, France
| | - Frédérique Bidard
- IFP Energies Nouvelles, 1 et 4 avenue de Bois-Préau, 92852, Rueil-Malmaison, France
| | - Etienne Jourdier
- IFP Energies Nouvelles, 1 et 4 avenue de Bois-Préau, 92852, Rueil-Malmaison, France
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35
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Onoue Y, Takekawa N, Nishikino T, Kojima S, Homma M. The role of conserved charged residues in the bidirectional rotation of the bacterial flagellar motor. Microbiologyopen 2018; 7:e00587. [PMID: 29573373 PMCID: PMC6079164 DOI: 10.1002/mbo3.587] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 12/19/2017] [Accepted: 12/28/2017] [Indexed: 12/23/2022] Open
Abstract
Many bacteria rotate their flagella both counterclockwise (CCW) and clockwise (CW) to achieve swimming toward attractants or away from repellents. Highly conserved charged residues are important for that motility, which suggests that electrostatic interactions are crucial for the rotor-stator function. It remains unclear if those residues contribute equally to rotation in the CCW and CW directions. To address this uncertainty, in this study, we expressed chimeric rotors and stators from Vibrio alginolyticus and Escherichia coli in E. coli, and measured the rotational speed of each motor in both directions using a tethered-cell assay. In wild-type cells, the rotational speeds in both directions were equal, as demonstrated previously. Some charge-neutralizing residue replacements in the stator decreased the rotational speed in both directions to the same extent. However, mutations in two charged residues in the rotor decreased the rotational speed only in the CCW direction. Subsequent analysis and previous results suggest that these amino acid residues are involved in supporting the conformation of the rotor, which is important for proper torque generation in the CCW direction.
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Affiliation(s)
- Yasuhiro Onoue
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Norihiro Takekawa
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Tatsuro Nishikino
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - 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
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36
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Kinoshita M, Namba K, Minamino T. Effect of a clockwise-locked deletion in FliG on the FliG ring structure of the bacterial flagellar motor. Genes Cells 2018; 23:241-247. [PMID: 29405551 DOI: 10.1111/gtc.12565] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 01/11/2018] [Indexed: 11/29/2022]
Abstract
FliG is a rotor protein of the bacterial flagellar motor. FliG consists of FliGN , FliGM and FliGC domains. Intermolecular FliGM -FliGC interactions promote FliG ring formation on the cytoplasmic face of the MS ring. A conformational change in HelixMC connecting FliGM and FliGC is responsible for the switching between the counterclockwise (CCW) and clockwise (CW) rotational states of the FliG ring. However, it remains unknown how it occurs. Here, we carried out in vivo disulfide cross-linking experiments to see the effect of a CW-locked deletion (∆PAA) in FliG on the FliG ring structure in Salmonella enterica. Higher-order oligomers were observed in the membrane fraction of the fliG(∆PAA + G166C/G194C) strain upon oxidation with iodine in a way similar to FliG(G166C/G194C), indicating that the PAA deletion does not inhibit domain-swap polymerization of FliG. FliG(∆PAA + E174C) formed a cross-linked homodimer whereas FliG(E174C) did not, indicating that Glu174 in HelixMC of one FliG protomer is located much closer to that of its neighboring subunit in the CW motor than in the CCW motor. We will discuss possible helical rearrangements of HelixMC that induce a structural remodeling of the FliG ring upon flagellar motor switching.
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Affiliation(s)
- Miki Kinoshita
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.,Quantitative Biology Center, RIKEN, Osaka, Japan
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
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37
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Kinoshita M, Furukawa Y, Uchiyama S, Imada K, Namba K, Minamino T. Insight into adaptive remodeling of the rotor ring complex of the bacterial flagellar motor. Biochem Biophys Res Commun 2017; 496:12-17. [PMID: 29294326 DOI: 10.1016/j.bbrc.2017.12.118] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 12/04/2017] [Accepted: 12/20/2017] [Indexed: 12/23/2022]
Abstract
The bacterial flagellar motor rotates in both counterclockwise (CCW) and clockwise (CW) directions. FliG, FliM and FliN form the C ring on the cytoplasmic face of the MS ring made of a transmembrane protein, FliF. The C ring acts not only as a rotor but also as a switch of the direction of motor rotation. FliG consists of three domains: FliGN, FliGM and FliGC. FliGN directly binds to FliF. Intermolecular interactions between FliGM and FliGC drive FliG ring formation. FliGM is responsible for the interaction with FliM. FliGC is involved in the interaction with the stator protein MotA. Adaptive remodeling of the C ring occurs when the motor switches between the CCW and CW states. However, it remained unknown how. Here, we report the effects of a CW-locked deletion mutation (ΔPEV) in FliG of Thermotaoga maritia (Tm-FliG) on FliG-FliG and FliG-FliM interactions. The PEV deletion stabilized the intramolecular interaction between FliGM and FliGC, thereby suppressing the oligomerization of Tm-FliGMC in solution. This deletion also induced a conformational change of HelixMC connecting FliGM and FliGC to reduce the binding affinity of Tm-FliGMC for FliM. We will discuss adaptive remodeling of the C ring responsible for flagellar motor switching.
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Affiliation(s)
- Miki Kinoshita
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadoaka, Suita, Osaka 565-0871, Japan
| | - Yukio Furukawa
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadoaka, Suita, Osaka 565-0871, Japan
| | - Susumu Uchiyama
- Graduate School of Engineering, Osaka University, 2-1 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
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadoaka, Suita, Osaka 565-0871, Japan; Quantitative Biology Center, RIKEN, 1-3 Yamadoaka, Suita, Osaka 565-0871, Japan
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadoaka, Suita, Osaka 565-0871, Japan.
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38
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Terahara N, Kodera N, Uchihashi T, Ando T, Namba K, Minamino T. Na +-induced structural transition of MotPS for stator assembly of the Bacillus flagellar motor. SCIENCE ADVANCES 2017; 3:eaao4119. [PMID: 29109979 PMCID: PMC5665596 DOI: 10.1126/sciadv.aao4119] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/06/2017] [Indexed: 05/03/2023]
Abstract
The bacterial flagellar motor consists of a rotor and a dozen stator units and regulates the number of active stator units around the rotor in response to changes in the environment. The MotPS complex is a Na+-type stator unit in the Bacillus subtilis flagellar motor and binds to the peptidoglycan layer through the peptidoglycan-binding (PGB) domain of MotS to act as the stator. The MotPS complex is activated in response to an increase in the Na+ concentration in the environment, but the mechanism of this activation has remained unknown. We report that activation occurs by a Na+-induced folding and dimer formation of the PGB domain of MotS, as revealed in real-time imaging by high-speed atomic force microscopy. The MotPS complex showed two distinct ellipsoid domains connected by a flexible linker. A smaller domain, corresponding to the PGB domain, became structured and unstructured in the presence and absence of 150 mM NaCl, respectively. When the amino-terminal portion of the PGB domain adopted a partially stretched conformation in the presence of NaCl, the center-to-center distance between these two domains increased by up to 5 nm, allowing the PGB domain to reach and bind to the peptidoglycan layer. We propose that assembly of the MotPS complex into a motor proceeds by means of Na+-induced structural transitions of its PGB domain.
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Affiliation(s)
- Naoya Terahara
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Noriyuki Kodera
- Bio-AFM Frontier Research Center, Kanazawa University, Kanazawa 920-1192, Japan
| | - Takayuki Uchihashi
- Bio-AFM Frontier Research Center, Kanazawa University, Kanazawa 920-1192, Japan
- Department of Physics, Kanazawa University, Kanazawa 920-1192, Japan
- Department of Physics, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Toshio Ando
- Bio-AFM Frontier Research Center, Kanazawa University, Kanazawa 920-1192, Japan
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Goban-cho, Chiyoda-ku, Tokyo 102-0076, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
- Quantitative Biology Center, RIKEN, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
- Corresponding author. (T.M.); (K.N.)
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
- Corresponding author. (T.M.); (K.N.)
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Impact of fluorescent protein fusions on the bacterial flagellar motor. Sci Rep 2017; 7:12583. [PMID: 28974721 PMCID: PMC5626733 DOI: 10.1038/s41598-017-11241-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 08/22/2017] [Indexed: 01/16/2023] Open
Abstract
Fluorescent fusion proteins open a direct and unique window onto protein function. However, they also introduce the risk of perturbation of the function of the native protein. Successful applications of fluorescent fusions therefore rely on a careful assessment and minimization of the side effects, but such insight is still lacking for many applications. This is particularly relevant in the study of the internal dynamics of motor proteins, where both the chemical and mechanical reaction coordinates can be affected. Fluorescent proteins fused to the stator of the Bacterial Flagellar Motor (BFM) have previously been used to unveil the motor subunit dynamics. Here we report the effects on single motors of three fluorescent proteins fused to the stators, all of which altered BFM behavior. The torque generated by individual stators was reduced while their stoichiometry remained unaffected. MotB fusions decreased the switching frequency and induced a novel bias-dependent asymmetry in the speed in the two directions. These effects could be mitigated by inserting a linker at the fusion point. These findings provide a quantitative account of the effects of fluorescent fusions to the stator on BFM dynamics and their alleviation- new insights that advance the use of fluorescent fusions to probe the dynamics of protein complexes.
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40
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Pourjaberi SNS, Terahara N, Namba K, Minamino T. The role of a cytoplasmic loop of MotA in load-dependent assembly and disassembly dynamics of the MotA/B stator complex in the bacterial flagellar motor. Mol Microbiol 2017; 106:646-658. [DOI: 10.1111/mmi.13843] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/18/2017] [Indexed: 11/26/2022]
Affiliation(s)
| | - Naoya Terahara
- Graduate School of Frontier Biosciences; Osaka University, 1-3 Yamadaoka; Suita Osaka 565-0871 Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences; Osaka University, 1-3 Yamadaoka; Suita Osaka 565-0871 Japan
- RIKEN; Quantitative Biology Center, 1-3 Yamadaoka; Suita Osaka 565-0871 Japan
| | - Tohru Minamino
- Graduate School of Frontier Biosciences; Osaka University, 1-3 Yamadaoka; Suita Osaka 565-0871 Japan
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41
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Zhang H, Lam KH, Lam WWL, Wong SYY, Chan VSF, Au SWN. A putative spermidine synthase interacts with flagellar switch protein FliM and regulates motility inHelicobacter pylori. Mol Microbiol 2017; 106:690-703. [DOI: 10.1111/mmi.13829] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2017] [Indexed: 12/25/2022]
Affiliation(s)
- Huawei Zhang
- Centre for Protein Science and Crystallography, School of Life Sciences; The Chinese University of Hong Kong; Hong Kong
| | - Kwok Ho Lam
- Centre for Protein Science and Crystallography, School of Life Sciences; The Chinese University of Hong Kong; Hong Kong
| | - Wendy Wai Ling Lam
- Centre for Protein Science and Crystallography, School of Life Sciences; The Chinese University of Hong Kong; Hong Kong
| | - Sandra Yuen Yuen Wong
- Division of Rheumatology & Clinical Immunology, Department of Medicine, Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong
| | - Vera Sau Fong Chan
- Division of Rheumatology & Clinical Immunology, Department of Medicine, Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong
| | - Shannon Wing Ngor Au
- Centre for Protein Science and Crystallography, School of Life Sciences; The Chinese University of Hong Kong; Hong Kong
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42
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Chelliah R, Wei S, Park BJ, Kim SH, Park DS, Kim SH, Hwan KS, Oh DH. Novel motB as a potential predictive tool for identification of B. cereus, B. thuringiensis and differentiation from other Bacillus species by triplex real-time PCR. Microb Pathog 2017; 111:22-27. [PMID: 28778821 DOI: 10.1016/j.micpath.2017.07.050] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 06/28/2017] [Accepted: 07/31/2017] [Indexed: 10/19/2022]
Abstract
Quantitative triplex real-time PCR (qPCR) offers an alternative method for detection of bacterial contamination. It provides quantitation of the number of gene copies. In our study, we established a qPCR assay to detect and quantify the specificity towards Bacillus cereus and B. thuringiensis. The assay was designed to detect a 280 bp fragment of motB gene encoding the flagellar motor protein, specific for detection of B. cereus and B. thuringiensis, excluding other group species B. pseudomycoides, B. mycoides and B. weihenstephanensis. Specificity of the assay was confirmed with 111 strains belonging to Bacillus cereus group and performed against 58 B. cereus, 50 B. thuringiensis, 3 other Bacillus bacteria and 9 non-Bacillus bacteria. Detection limit was determined for each assay. Direct analysis of samples revealed the specificity towards identification and characterization of B. cereus group cultured in nutrient media. Based on results, it was observed that motB showed 97% specificity towards B. cereus strains, 98% for B. thuringiensis but other B. cereus group showed less sensitivity (0%), thus, provides an efficient tool to identify B. cereus and B. thuringiensis. Further, environmental and food samples do not require band isolation, re-amplification or sequence identification. Thus, reducing the time and cost of analysis.
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Affiliation(s)
- Ramachandran Chelliah
- Department of Food Science and Biotechnology, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Shuai Wei
- Department of Food Science and Biotechnology, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Byung-Jae Park
- Department of Food Science and Biotechnology, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Se-Hun Kim
- Department of Food Science and Biotechnology, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Dong-Suk Park
- Department of Agricultural Biotechnology, National Academy of Agricultural Science, Rural Development Administration, Jeonju, 54874, Republic of Korea
| | - Soon Han Kim
- Food Microbiology Division, National Institute of Food and Drug Safety Evaluation, 187, Osongsaengmyeong 2-ro, Osong-eup, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do, 28159, Republic of Korea
| | - Kim Seok Hwan
- Food Microbiology Division, National Institute of Food and Drug Safety Evaluation, 187, Osongsaengmyeong 2-ro, Osong-eup, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do, 28159, Republic of Korea
| | - Deog-Hwan Oh
- Department of Food Science and Biotechnology, Kangwon National University, Chuncheon, 24341, Republic of Korea.
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Kim EA, Panushka J, Meyer T, Ide N, Carlisle R, Baker S, Blair DF. Biogenesis of the Flagellar Switch Complex in Escherichia coli: Formation of Sub-Complexes Independently of the Basal-Body MS-Ring. J Mol Biol 2017. [PMID: 28625846 DOI: 10.1016/j.jmb.2017.06.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Direction switching in the flagellar motor of Escherichia coli is under the control of a complex on the rotor formed from the proteins FliG, FliM, and FliN. FliG lies at the top of the switch complex (i.e., nearest the membrane) and is arranged with its C-terminal domain (FliGC) resting on the middle domain (FliGM) of the neighboring subunit. This organization requires the protein to adopt an open conformation that exposes the surfaces engaging in intersubunit FliGC/FliGM contacts. In a recent study, Baker and coworkers [13] obtained evidence that FliG in the cytosol is monomeric and takes on a more compact conformation, with FliGC making intramolecular contact with FliGM of the same subunit. In the present work, we examine the conformational preferences and interactions of FliG through in vivo crosslinking experiments in cells that lack either all other flagellar proteins or just the MS-ring protein FliF. The results indicate that FliG has a significant tendency to form multimers independently of other flagellar components. The multimerization of FliG is promoted by FliF and also by FliM. FliM does not multimerize efficiently by itself but does so in the presence of FliG. Thus, pre-assemblies of the switch-complex proteins can form in the cytosol and might function as intermediates in assembly.
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Affiliation(s)
- Eun A Kim
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Joseph Panushka
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Trevor Meyer
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Nicholas Ide
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Ryan Carlisle
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Samantha Baker
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - David F Blair
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA.
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Weller‐Stuart T, Toth I, De Maayer P, Coutinho T. Swimming and twitching motility are essential for attachment and virulence of Pantoea ananatis in onion seedlings. MOLECULAR PLANT PATHOLOGY 2017; 18:734-745. [PMID: 27226224 PMCID: PMC6638301 DOI: 10.1111/mpp.12432] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 05/23/2016] [Accepted: 05/24/2016] [Indexed: 05/05/2023]
Abstract
Pantoea ananatis is a widespread phytopathogen with a broad host range. Despite its ability to infect economically important crops, such as maize, rice and onion, relatively little is known about how this bacterium infects and colonizes host tissue or spreads within and between hosts. To study the role of motility in pathogenicity, we analysed both swimming and twitching motility in P. ananatis LMG 20103. Genetic recombineering was used to construct four mutants affected in motility. Two flagellar mutants were disrupted in the flgK and motA genes, required for flagellar assembly and flagellar rotation, respectively. Similarly, two twitching motility mutants were generated, impaired in the structure (pilA) and functioning (pilT) of the type IV pili. The role of swimming and twitching motility during the infection cycle of P. ananatis in onion seedlings was determined by comparing the mutant- and wild-type strains using several in vitro and in planta assays. From the results obtained, it was evident that flagella aid P. ananatis in locating and attaching to onion leaf surfaces, as well as in pathogenicity, whereas twitching motility is instrumental in the spread of the bacteria on the surface once attachment has occurred. Both swimming and twitching motility contribute towards the ability of P. ananatis to cause disease in onions.
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Affiliation(s)
- Tania Weller‐Stuart
- Department of Microbiology, Forestry and Agricultural Biotechnology Institute (FABI)University of PretoriaPretoria0002 South Africa
| | - Ian Toth
- Department of Microbiology, Forestry and Agricultural Biotechnology Institute (FABI)University of PretoriaPretoria0002 South Africa
- Cell and Molecular SciencesThe James Hutton InstituteDundeeDD2 5DA UK
| | - Pieter De Maayer
- Department of Microbiology, Centre of Microbial Ecology and Genomics (CMEG)University of PretoriaPretoria0002 South Africa
| | - Teresa Coutinho
- Department of Microbiology, Forestry and Agricultural Biotechnology Institute (FABI)University of PretoriaPretoria0002 South Africa
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Terahara N, Noguchi Y, Nakamura S, Kami-Ike N, Ito M, Namba K, Minamino T. Load- and polysaccharide-dependent activation of the Na +-type MotPS stator in the Bacillus subtilis flagellar motor. Sci Rep 2017; 7:46081. [PMID: 28378843 PMCID: PMC5380961 DOI: 10.1038/srep46081] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 03/09/2017] [Indexed: 01/07/2023] Open
Abstract
The flagellar motor of Bacillus subtilis possesses two distinct H+-type MotAB and Na+-type MotPS stators. In contrast to the MotAB motor, the MotPS motor functions efficiently at elevated viscosity in the presence of 200 mM NaCl. Here, we analyzed the torque-speed relationship of the Bacillus MotAB and MotPS motors over a wide range of external loads. The stall torque of the MotAB and MotPS motors at high load was about 2,200 pN nm and 220 pN nm, respectively. The number of active stators in the MotAB and MotPS motors was estimated to be about ten and one, respectively. However, the number of functional stators in the MotPS motor was increased up to ten with an increase in the concentration of a polysaccharide, Ficoll 400, as well as in the load. The maximum speeds of the MotAB and MotPS motors at low load were about 200 Hz and 50 Hz, respectively, indicating that the rate of the torque-generation cycle of the MotPS motor is 4-fold slower than that of the MotAB motor. Domain exchange experiments showed that the C-terminal periplasmic domain of MotS directly controls the assembly and disassembly dynamics of the MotPS stator in a load- and polysaccharide-dependent manner.
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Affiliation(s)
- Naoya Terahara
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yukina Noguchi
- Graduate School of Life Sciences, Toyo University, 1-1-1 Izumino, Itakura-machi, Oura-gun, Gunma 374-0193, Japan
| | - Shuichi Nakamura
- Department of Applied Physics, Tohoku University, 6-6-05 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Nobunori Kami-Ike
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Masahiro Ito
- Graduate School of Life Sciences, Toyo University, 1-1-1 Izumino, Itakura-machi, Oura-gun, Gunma 374-0193, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan.,Quantitative Biology Center, RIKEN, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
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Abstract
Fluorescence imaging techniques using green fluorescent protein (GFP) and related fluorescent proteins are utilized to monitor and analyze a wide range of biological processes in living cells. Stepwise photobleaching experiments can determine the stoichiometry of protein complexes. Fluorescence recovery after photobleaching (FRAP) experiments can reveal in vivo dynamics of biomolecules. In this chapter, we describe methods to detect the subcellular localization, stoichiometry, and turnovers of stator and rotor components of the Salmonella flagellar motor.
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Ito M, Takahashi Y. Nonconventional cation-coupled flagellar motors derived from the alkaliphilic Bacillus and Paenibacillus species. Extremophiles 2016; 21:3-14. [PMID: 27771767 DOI: 10.1007/s00792-016-0886-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 10/10/2016] [Indexed: 12/21/2022]
Abstract
Prior to 2008, all previously studied conventional bacterial flagellar motors appeared to utilize either H+ or Na+ as coupling ions. Membrane-embedded stator complexes support conversion of energy using transmembrane electrochemical ion gradients. The main H+-coupled stators, known as MotAB, differ from Na+-coupled stators, PomAB of marine bacteria, and MotPS of alkaliphilic Bacillus. However, in 2008, a MotAB-type flagellar motor of alkaliphilic Bacillus clausii KSM-K16 was revealed as an exception with the first dual-function motor. This bacterium was identified as the first bacterium with a single stator-rotor that can utilize both H+ and Na+ for ion-coupling at different pH ranges. Subsequently, another exception, a MotPS-type flagellar motor of alkaliphilic Bacillus alcalophilus AV1934, was reported to utilize Na+ plus K+ and Rb+ as coupling ions for flagellar rotation. In addition, the alkaline-tolerant bacterium Paenibacillus sp. TCA20, which can utilize divalent cations such as Ca2+, Mg2+, and Sr2+, was recently isolated from a hot spring in Japan, which contains a high Ca2+ concentration. These findings show that bacterial flagellar motors isolated from unique environments utilize unexpected coupling ions. This suggests that bacteria that grow in different extreme environments adapt to local conditions and evolve their motility machinery.
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Affiliation(s)
- Masahiro Ito
- Faculty of Life Sciences, Toyo University, Oura-gun, Gunma, 374-0193, Japan. .,Bio-nano Electronics Research Center, Toyo University, Kawagoe, Saitama, 350-8585, Japan.
| | - Yuka Takahashi
- Bio-nano Electronics Research Center, Toyo University, Kawagoe, Saitama, 350-8585, Japan
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Licata NA, Mohari B, Fuqua C, Setayeshgar S. Diffusion of Bacterial Cells in Porous Media. Biophys J 2016; 110:247-57. [PMID: 26745427 DOI: 10.1016/j.bpj.2015.09.035] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 09/22/2015] [Accepted: 09/30/2015] [Indexed: 12/24/2022] Open
Abstract
The chemotaxis signal transduction network regulates the biased random walk of many bacteria in favorable directions and away from harmful ones through modulating the frequency of directional reorientations. In mutants of diverse bacteria lacking the chemotaxis response, migration in classic motility agar, which constitutes a fluid-filled porous medium, is compromised; straight-swimming cells unable to tumble become trapped within the agar matrix. Spontaneous mutations that restore spreading have been previously observed in the enteric bacterium Escherichia coli, and recent work in other bacterial species has isolated and quantified different classes of nonchemotacting mutants exhibiting the same spreading phenotype. We present a theoretical description of bacterial diffusion in a porous medium-the natural habitat for many cell types-which elucidates how diverse modifications of the motility apparatus resulting in a nonzero tumbling frequency allows for unjamming of otherwise straight-swimming cells at internal boundaries and leads to net migration. A unique result of our analysis is increasing diffusive spread with increasing tumbling frequency in the small pore limit, consistent with earlier experimental observations but not captured by previous models. Our theoretical results, combined with a simple model of bacterial diffusion and growth in agar, are compared with our experimental measurements of swim ring expansion as a function of time, demonstrating good quantitative agreement. Our results suggest that the details of the cellular tumbling process may be adapted to enable bacteria to propagate efficiently through complex environments. For engineered, self-propelled microswimmers that navigate via alternating straight runs and changes in direction, these results suggest an optimal reorientation strategy for efficient migration in a porous environment with a given microarchitecture.
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Affiliation(s)
- Nicholas A Licata
- Department of Physics, Indiana University, Bloomington, Indiana; Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, Michigan
| | - Bitan Mohari
- Department of Biology, Indiana University, Bloomington, Indiana
| | - Clay Fuqua
- Department of Biology, Indiana University, Bloomington, Indiana
| | - Sima Setayeshgar
- Department of Physics, Indiana University, Bloomington, Indiana.
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49
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The tetrameric MotA complex as the core of the flagellar motor stator from hyperthermophilic bacterium. Sci Rep 2016; 6:31526. [PMID: 27531865 PMCID: PMC4987623 DOI: 10.1038/srep31526] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 07/20/2016] [Indexed: 11/09/2022] Open
Abstract
Rotation of bacterial flagellar motor is driven by the interaction between the stator and rotor, and the driving energy is supplied by ion influx through the stator channel. The stator is composed of the MotA and MotB proteins, which form a hetero-hexameric complex with a stoichiometry of four MotA and two MotB molecules. MotA and MotB are four- and single-transmembrane proteins, respectively. To generate torque, the MotA/MotB stator unit changes its conformation in response to the ion influx, and interacts with the rotor protein FliG. Here, we overproduced and purified MotA of the hyperthermophilic bacterium Aquifex aeolicus. A chemical crosslinking experiment revealed that MotA formed a multimeric complex, most likely a tetramer. The three-dimensional structure of the purified MotA, reconstructed by electron microscopy single particle imaging, consisted of a slightly elongated globular domain and a pair of arch-like domains with spiky projections, likely to correspond to the transmembrane and cytoplasmic domains, respectively. We show that MotA molecules can form a stable tetrameric complex without MotB, and for the first time, demonstrate the cytoplasmic structure of the stator.
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50
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Ha R, Frirdich E, Sychantha D, Biboy J, Taveirne ME, Johnson JG, DiRita VJ, Vollmer W, Clarke AJ, Gaynor EC. Accumulation of Peptidoglycan O-Acetylation Leads to Altered Cell Wall Biochemistry and Negatively Impacts Pathogenesis Factors of Campylobacter jejuni. J Biol Chem 2016; 291:22686-22702. [PMID: 27474744 PMCID: PMC5077204 DOI: 10.1074/jbc.m116.746404] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Indexed: 12/30/2022] Open
Abstract
Campylobacter jejuni is a leading cause of bacterial gastroenteritis in the developed world. Despite its prevalence, its mechanisms of pathogenesis are poorly understood. Peptidoglycan (PG) is important for helical shape, colonization, and host-pathogen interactions in C. jejuni Therefore, changes in PG greatly impact the physiology of this organism. O-acetylation of peptidoglycan (OAP) is a bacterial phenomenon proposed to be important for proper cell growth, characterized by acetylation of the C6 hydroxyl group of N-acetylmuramic acid in the PG glycan backbone. The OAP gene cluster consists of a PG O-acetyltransferase A (patA) for translocation of acetate into the periplasm, a PG O-acetyltransferase B (patB) for O-acetylation, and an O-acetylpeptidoglycan esterase (ape1) for de-O-acetylation. In this study, reduced OAP in ΔpatA and ΔpatB had minimal impact on C. jejuni growth and fitness under the conditions tested. However, accumulation of OAP in Δape1 resulted in marked differences in PG biochemistry, including O-acetylation, anhydromuropeptide levels, and changes not expected to result directly from Ape1 activity. This suggests that OAP may be a form of substrate level regulation in PG biosynthesis. Ape1 acetylesterase activity was confirmed in vitro using p-nitrophenyl acetate and O-acetylated PG as substrates. In addition, Δape1 exhibited defects in pathogenesis-associated phenotypes, including cell shape, motility, biofilm formation, cell surface hydrophobicity, and sodium deoxycholate sensitivity. Δape1 was also impaired for chick colonization and adhesion, invasion, intracellular survival, and induction of IL-8 production in INT407 cells in vitro The importance of Ape1 in C. jejuni biology makes it a good candidate as an antimicrobial target.
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Affiliation(s)
- Reuben Ha
- From the Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Emilisa Frirdich
- From the Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - David Sychantha
- the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Jacob Biboy
- the Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4AX, United Kingdom, and
| | - Michael E Taveirne
- the Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Jeremiah G Johnson
- the Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Victor J DiRita
- the Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Waldemar Vollmer
- the Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4AX, United Kingdom, and
| | - Anthony J Clarke
- the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Erin C Gaynor
- From the Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada,
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