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Nishikino T, Sagara Y, Terashima H, Homma M, Kojima S. Hoop-like role of the cytosolic interface helix in Vibrio PomA, an ion-conducting membrane protein, in the bacterial flagellar motor. J Biochem 2022; 171:443-450. [PMID: 35015887 DOI: 10.1093/jb/mvac001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/04/2022] [Indexed: 11/13/2022] Open
Abstract
Vibrio has a polar flagellum driven by sodium ions for swimming. The force-generating stator unit consists of PomA and PomB. PomA contains four-transmembrane regions and a cytoplasmic domain of approximately 100 residues which interacts with the rotor protein, FliG, to be important for the force generation of rotation. The three-dimensional structure of the stator shows that the cytosolic interface (CI) helix of PomA is located parallel to the inner membrane. In this study, we investigated the function of CI helix and its role as stator. Systematic proline mutagenesis showed that residues K64, F66, and M67 were important for this function. The mutant stators did not assemble around the rotor. Moreover, the growth defect caused by PomB plug deletion was suppressed by these mutations. We speculate that the mutations affect the structure of the helices extending from TM3 and TM4 and reduce the structural stability of the stator complex. This study suggests that the helices parallel to the inner membrane play important roles in various processes, such as the hoop-like function in securing the stability of the stator complex and the ion conduction pathway, which may lead to the elucidation of the ion permeation and assembly mechanism of the stator.
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Affiliation(s)
- Tatsuro Nishikino
- Institute for protein research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yugo Sagara
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Hiroyuki Terashima
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.,Department of bacteriology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
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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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3
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Tusk SE, Delalez NJ, Berry RM. Subunit Exchange in Protein Complexes. J Mol Biol 2018; 430:4557-4579. [DOI: 10.1016/j.jmb.2018.06.039] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 06/21/2018] [Accepted: 06/21/2018] [Indexed: 01/09/2023]
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4
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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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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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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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Mohawk KL, Poly F, Sahl JW, Rasko DA, Guerry P. High frequency, spontaneous motA mutations in Campylobacter jejuni strain 81-176. PLoS One 2014; 9:e88043. [PMID: 24558375 PMCID: PMC3928116 DOI: 10.1371/journal.pone.0088043] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 01/02/2014] [Indexed: 12/28/2022] Open
Abstract
Campylobacter jejuni is an important cause of bacterial diarrhea worldwide. The pathogenesis of C. jejuni is poorly understood and complicated by phase variation of multiple surface structures including lipooligosaccharide, capsule, and flagellum. When C. jejuni strain 81-176 was plated on blood agar for single colonies, the presence of translucent, non-motile colonial variants was noted among the majority of opaque, motile colonies. High-throughput genomic sequencing of two flagellated translucent and two opaque variants as well as the parent strain revealed multiple genetic changes compared to the published genome. However, the only mutated open reading frame common between the two translucent variants and absent from the opaque variants and the parent was motA, encoding a flagellar motor protein. A total of 18 spontaneous motA mutations were found that mapped to four distinct sites in the gene, with only one class of mutation present in a phase variable region. This study exemplifies the mutative/adaptive properties of C. jejuni and demonstrates additional variability in C. jejuni beyond phase variation.
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Affiliation(s)
- Krystle L. Mohawk
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, United States of America
| | - Frédéric Poly
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, United States of America
| | - Jason W. Sahl
- Institute for Genome Sciences, Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - David A. Rasko
- Institute for Genome Sciences, Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Patricia Guerry
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, United States of America
- * E-mail:
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Contribution of many charged residues at the stator-rotor interface of the Na+-driven flagellar motor to torque generation in Vibrio alginolyticus. J Bacteriol 2014; 196:1377-85. [PMID: 24464458 DOI: 10.1128/jb.01392-13] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In torque generation by the bacterial flagellar motor, it has been suggested that electrostatic interactions between charged residues of MotA and FliG at the rotor-stator interface are important. However, the actual role(s) of those charged residues has not yet been clarified. In this study, we systematically made mutants of Vibrio alginolyticus whose charged residues of PomA (MotA homologue) and FliG were replaced by uncharged or charge-reversed residues and characterized the motilities of those mutants. We found that the members of a group of charged residues, 7 in PomA and 6 in FliG, collectively participate in torque generation of the Na(+)-driven flagellar motor in Vibrio. An additional specific interaction between PomA-E97 and FliG-K284 is critical for proper performance of the Vibrio motor. Our results also reveal that more charged residues are involved in the PomA-FliG interactions in the Vibrio Na(+)-driven motor than in the MotA-FliG interactions in the H(+)-driven one. This suggests that a larger number of conserved charged residues at the PomA-FliG interface contributes to the robustness of the Vibrio motor against mutations. The interaction surfaces of the stator and rotor of the Na(+)-driven motor seem to be more complex than those previously proposed in the H(+)-driven motor.
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Onoue Y, Abe-Yoshizumi R, Gohara M, Kobayashi S, Nishioka N, Kojima S, Homma M. Construction of functional fragments of the cytoplasmic loop with the C-terminal region of PomA, a stator component of the Vibrio Na+ driven flagellar motor. J Biochem 2014; 155:207-16. [DOI: 10.1093/jb/mvt115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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10
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Abe-Yoshizumi R, Kobayashi S, Gohara M, Hayashi K, Kojima C, Kojima S, Sudo Y, Asami Y, Homma M. Expression, purification and biochemical characterization of the cytoplasmic loop of PomA, a stator component of the Na(+) driven flagellar motor. Biophysics (Nagoya-shi) 2013; 9:21-9. [PMID: 27493537 PMCID: PMC4629686 DOI: 10.2142/biophysics.9.21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 01/08/2013] [Indexed: 12/30/2022] Open
Abstract
Flagellar motors embedded in bacterial membranes are molecular machines powered by specific ion flows. Each motor is composed of a stator and a rotor and the interactions of those components are believed to generate the torque. Na+ influx through the PomA/PomB stator complex of Vibrio alginolyticus is coupled to torque generation and is speculated to trigger structural changes in the cytoplasmic domain of PomA that interacts with a rotor protein in the C-ring, FliG, to drive the rotation. In this study, we tried to overproduce the cytoplasmic loop of PomA (PomA-Loop), but it was insoluble. Thus, we made a fusion protein with a small soluble tag (GB1) which allowed us to express and characterize the recombinant protein. The structure of the PomA-Loop seems to be very elongated or has a loose tertiary structure. When the PomA-Loop protein was produced in E. coli, a slight dominant effect was observed on motility. We conclude that the cytoplasmic loop alone retains a certain function.
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Affiliation(s)
- Rei Abe-Yoshizumi
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Shiori Kobayashi
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Mizuki Gohara
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Kokoro Hayashi
- Laboratory of Biophysics, Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Chojiro Kojima
- Laboratory of Biophysics, Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Yuki Sudo
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Yasuo Asami
- TA Instruments Japan, Inc., 5-2-4, Nishi-gotanda, Shinagawa-ku, Tokyo 141-0031, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
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11
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Characterization of PomA mutants defective in the functional assembly of the Na(+)-driven flagellar motor in Vibrio alginolyticus. J Bacteriol 2012; 194:1934-9. [PMID: 22343296 DOI: 10.1128/jb.06552-11] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The polar flagellar motor of Vibrio alginolyticus rotates using Na(+) influx through the stator, which is composed of 2 subunits, PomA and PomB. About a dozen stators dynamically assemble around the rotor, depending on the Na(+) concentration in the surrounding environment. The motor torque is generated by the interaction between the cytoplasmic domain of PomA and the C-terminal region of FliG, a component of the rotor. We had shown previously that mutations of FliG affected the stator assembly around the rotor, which suggested that the PomA-FliG interaction is required for the assembly. In this study, we examined the effects of various mutations mainly in the cytoplasmic domain of PomA on that assembly. All mutant stators examined, which resulted in the loss of motor function, assembled at a lower level than did the wild-type PomA. A His tag pulldown assay showed that some mutations in PomA reduced the PomA-PomB interaction, but other mutations did not. Next, we examined the ion conductivity of the mutants using a mutant stator that lacks the plug domain, PomA/PomB(ΔL)(Δ41-120), which impairs cell growth by overproduction, presumably because a large amount of Na(+) is conducted into the cells. Some PomA mutations suppressed this growth inhibition, suggesting that such mutations reduce Na(+) conductivity, so that the stators could not assemble around the rotor. Only the mutation H136Y did not impair the stator formation and ion conductivity through the stator. We speculate that this particular mutation may affect the PomA-FliG interaction and prevent activation of the stator assembly around the rotor.
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12
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Abstract
The Na(+) -driven bacterial flagellar motor is a molecular machine powered by an electrochemical potential gradient of sodium ions across the cytoplasmic membrane. The marine bacterium Vibrio alginolyticus has a single polar flagellum that enables it to swim in liquid. The flagellar motor contains a basal body and a stator complexes, which are composed of several proteins. PomA, PomB, MotX, and MotY are thought to be essential components of the stator that are required to generate the torque of the rotation. Several mutations have been investigated to understand the characteristics and function of the ion channel in the stator and the mechanism of its assembly around the rotor to complete the motor. In this review, we summarize recent results of the Na(+) -driven motor in the polar flagellum of Vibrio.
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Affiliation(s)
- Na Li
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Japan
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Wilhelms M, Vilches S, Molero R, Shaw JG, Tomás JM, Merino S. Two redundant sodium-driven stator motor proteins are involved in Aeromonas hydrophila polar flagellum rotation. J Bacteriol 2009; 191:2206-17. [PMID: 19181813 PMCID: PMC2655530 DOI: 10.1128/jb.01526-08] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Accepted: 01/15/2009] [Indexed: 11/20/2022] Open
Abstract
Motility is an essential characteristic for mesophilic Aeromonas strains. We identified a new polar flagellum region (region 6) in the A. hydrophila AH-3 (serotype O34) chromosome that contained two additional polar stator genes, named pomA2 and pomB2. A. hydrophila PomA2 and PomB2 are highly homologous to other sodium-conducting polar flagellum stator motors as well as to the previously described A. hydrophila AH-3 PomA and PomB. pomAB and pomA2B2 were present in all the mesophilic Aeromonas strains tested and were independent of the strains' ability to produce lateral flagella. Unlike MotX, which is a stator protein that is essential for polar flagellum rotation, here we demonstrate that PomAB and PomA2B2 are redundant sets of proteins, as neither set on its own is essential for polar flagellum motility in either aqueous or high-viscosity environments. Both PomAB and PomA2B2 are sodium-coupled stator complexes, although PomA2B2 is more sensitive to low concentrations of sodium than PomAB. Furthermore, the level of transcription in aqueous and high-viscosity environments of pomA2B2 is reduced compared to that of pomAB. The A. hydrophila AH-3 polar flagellum is the first case described in which two redundant sodium-driven stator motor proteins (PomAB and PomA2B2) are found.
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Affiliation(s)
- Markus Wilhelms
- Departamento Microbiología, Universidad Barcelona, Diagonal, Spain
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Paulick A, Koerdt A, Lassak J, Huntley S, Wilms I, Narberhaus F, Thormann KM. Two different stator systems drive a single polar flagellum inShewanella oneidensisMR-1. Mol Microbiol 2009; 71:836-50. [DOI: 10.1111/j.1365-2958.2008.06570.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Terashima H, Kojima S, Homma M. Flagellar motility in bacteria structure and function of flagellar motor. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 270:39-85. [PMID: 19081534 DOI: 10.1016/s1937-6448(08)01402-0] [Citation(s) in RCA: 174] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Bacterial flagella are filamentous organelles that drive cell locomotion. They thrust cells in liquids (swimming) or on surfaces (swarming) so that cells can move toward favorable environments. At the base of each flagellum, a reversible rotary motor, which is powered by the proton- or the sodium-motive force, is embedded in the cell envelope. The motor consists of two parts: the rotating part, or rotor, that is connected to the hook and the filament, and the nonrotating part, or stator, that conducts coupling ion and is responsible for energy conversion. Intensive genetic and biochemical studies of the flagellum have been conducted in Salmonella typhimurium and Escherichia coli, and more than 50 gene products are known to be involved in flagellar assembly and function. The energy-coupling mechanism, however, is still not known. In this chapter, we survey our current knowledge of the flagellar system, based mostly on studies from Salmonella, E. coli, and marine species Vibrio alginolyticus, supplemented with distinct aspects of other bacterial species revealed by recent studies.
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Affiliation(s)
- Hiroyuki Terashima
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
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