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Nishikino T, Hijikata A, Kojima S, Shirai T, Kainosho M, Homma M, Miyanoiri Y. Changes in the hydrophobic network of the FliG MC domain induce rotational switching of the flagellar motor. iScience 2023; 26:107320. [PMID: 37520711 PMCID: PMC10372836 DOI: 10.1016/j.isci.2023.107320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 04/18/2023] [Accepted: 07/04/2023] [Indexed: 08/01/2023] Open
Abstract
The FliG protein plays a pivotal role in switching the rotational direction of the flagellar motor between clockwise and counterclockwise. Although we previously showed that mutations in the Gly-Gly linker of FliG induce a defect in switching rotational direction, the detailed molecular mechanism was not elucidated. Here, we studied the structural changes in the FliG fragment containing the middle and C-terminal regions, named FliGMC, and the switch-defective FliGMC-G215A, using nuclear magnetic resonance (NMR) and molecular dynamics simulations. NMR analysis revealed multiple conformations of FliGMC, and the exchange process between these conformations was suppressed by the G215A residue substitution. Furthermore, changes in the intradomain orientation of FliG were induced by changes in hydrophobic interaction networks throughout FliG. Our finding applies to FliG in a ring complex in the flagellar basal body, and clarifies the switching mechanism of the flagellar motor.
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Affiliation(s)
- Tatsuro Nishikino
- Laboratory for Ultra-High Magnetic Field NMR Spectroscopy, Research Center for Next-Generation Protein Sciences, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Atsushi Hijikata
- Department of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
| | - Seiji Kojima
- Division of Biological Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Tsuyoshi Shirai
- Department of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
| | - Masatsune Kainosho
- Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
- Graduate School of Science, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, Tokyo 192-0397, Japan
| | - Michio Homma
- Division of Biological Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
- Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Yohei Miyanoiri
- Laboratory for Ultra-High Magnetic Field NMR Spectroscopy, Research Center for Next-Generation Protein Sciences, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
- Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
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2
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Wordom update 2: A user-friendly program for the analysis of molecular structures and conformational ensembles. Comput Struct Biotechnol J 2023; 21:1390-1402. [PMID: 36817953 PMCID: PMC9929209 DOI: 10.1016/j.csbj.2023.01.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 01/29/2023] Open
Abstract
We present the second update of Wordom, a user-friendly and efficient program for manipulation and analysis of conformational ensembles from molecular simulations. The actual update expands some of the existing modules and adds 21 new modules to the update 1 published in 2011. The new adds can be divided into three sets that: 1) analyze atomic fluctuations and structural communication; 2) explore ion-channel conformational dynamics and ionic translocation; and 3) compute geometrical indices of structural deformation. Set 1 serves to compute correlations of motions, find geometrically stable domains, identify a dynamically invariant core, find changes in domain-domain separation and mutual orientation, perform wavelet analysis of large-scale simulations, process the output of principal component analysis of atomic fluctuations, perform functional mode analysis, infer regions of mechanical rigidity, analyze overall fluctuations, and perform the perturbation response scanning. Set 2 includes modules specific for ion channels, which serve to monitor the pore radius as well as water or ion fluxes, and measure functional collective motions like receptor twisting or tilting angles. Finally, set 3 includes tools to monitor structural deformations by computing angles, perimeter, area, volume, β-sheet curvature, radial distribution function, and center of mass. The ring perception module is also included, helpful to monitor supramolecular self-assemblies. This update places Wordom among the most suitable, complete, user-friendly, and efficient software for the analysis of biomolecular simulations. The source code of Wordom and the relative documentation are available under the GNU general public license at http://wordom.sf.net.
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3
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Kurniyati K, Chang Y, Liu J, Li C. Transcriptional and functional characterizations of multiple flagellin genes in spirochetes. Mol Microbiol 2022; 118:175-190. [PMID: 35776658 PMCID: PMC9481697 DOI: 10.1111/mmi.14959] [Citation(s) in RCA: 1] [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: 03/15/2022] [Revised: 06/28/2022] [Accepted: 06/28/2022] [Indexed: 11/28/2022]
Abstract
The flagellar filament is a helical propeller for bacterial locomotion. In external flagellates, the filaments are mostly homopolymers of a single flagellin protein. By contrast, the flagellar filaments of spirochetes are mostly heteropolymers of multiple flagellin proteins. This report seeks to investigate the role of multiple flagellin proteins using the oral spirochete Treponema denticola as a model. First, biochemical and genetic studies uncover that the flagellar filaments of T. denticola mainly comprise four proteins, FlaA, FlaB1, FlaB2, and FlaB3, in a defined stoichiometry. Second, transcriptional analyses reveal that the genes encoding these four proteins are regulated by two different transcriptional factors, sigma28 and sigma70 . Third, loss-of-function studies demonstrate that each individual flagellin protein contributes to spirochete motility, but none of them is absolutely required. Last, we provide genetic and structural evidence that FlaA forms a "seam"-like structure around the core and that deletion of individual flagellin protein alters the flagellar homeostasis. Collectively, these results demonstrate that T. denticola has evolved a unique mechanism to finely regulate its flagellar filament gene expression and assembly which renders the organelle with the right number, shape, strength, and structure for its distinct motility.
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Affiliation(s)
- Kurni Kurniyati
- Department of Oral Craniofacial Molecular Biology, School of DentistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Yunjie Chang
- Microbial Sciences InstituteYale UniversityWest HavenConnecticutUSA
- Department of Microbial PathogenesisYale School of MedicineNew HavenConnecticutUSA
| | - Jun Liu
- Microbial Sciences InstituteYale UniversityWest HavenConnecticutUSA
- Department of Microbial PathogenesisYale School of MedicineNew HavenConnecticutUSA
| | - Chunhao Li
- Department of Oral Craniofacial Molecular Biology, School of DentistryVirginia Commonwealth UniversityRichmondVirginiaUSA
- Department of Microbiology and Immunology, School of MedicineVirginia Commonwealth UniversityRichmondVirginiaUSA
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4
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Khan S. Conformational spread drives the evolution of the calcium-calmodulin protein kinase II. Sci Rep 2022; 12:8499. [PMID: 35589775 PMCID: PMC9120016 DOI: 10.1038/s41598-022-12090-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 05/03/2022] [Indexed: 11/17/2022] Open
Abstract
The calcium calmodulin (Ca2+/CaM) dependent protein kinase II (CaMKII) decodes Ca2+ frequency oscillations. The CaMKIIα isoform is predominantly expressed in the brain and has a central role in learning. I matched residue and organismal evolution with collective motions deduced from the atomic structure of the human CaMKIIα holoenzyme to learn how its ring architecture abets function. Protein dynamic simulations showed its peripheral kinase domains (KDs) are conformationally coupled via lateral spread along the central hub. The underlying β-sheet motions in the hub or association domain (AD) were deconvolved into dynamic couplings based on mutual information. They mapped onto a coevolved residue network to partition the AD into two distinct sectors. A second, energetically stressed sector was added to ancient bacterial enzyme dimers for assembly of the ringed hub. The continued evolution of the holoenzyme after AD–KD fusion targeted the sector’s ring contacts coupled to the KD. Among isoforms, the α isoform emerged last and, it alone, mutated rapidly after the poikilotherm–homeotherm jump to match the evolution of memory. The correlation between dynamics and evolution of the CaMKII AD argues single residue substitutions fine-tune hub conformational spread. The fine-tuning could increase CaMKIIα Ca2+ frequency response range for complex learning functions.
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Affiliation(s)
- Shahid Khan
- Molecular Biology Consortium, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA. .,SBA School of Science and Engineering, LUMS, Lahore, Pakistan. .,Laboratory of Cell Biology, NINDS, NIH, Bethesda, MD, 20892, USA.
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5
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Gupta R, Rhee KY, Beagle SD, Chawla R, Perdomo N, Lockless SW, Lele PP. Indole modulates cooperative protein-protein interactions in the flagellar motor. PNAS NEXUS 2022; 1. [PMID: 35719892 PMCID: PMC9205328 DOI: 10.1093/pnasnexus/pgac035] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Indole is a major component of the bacterial exometabolome, and the mechanisms for its wide-ranging effects on bacterial physiology are biomedically significant, although they remain poorly understood. Here, we determined how indole modulates the functions of a widely conserved motility apparatus, the bacterial flagellum. Our experiments in Escherichia coli revealed that indole influences the rotation rates and reversals in the flagellum’s direction of rotation via multiple mechanisms. At concentrations higher than 1 mM, indole decreased the membrane potential to dissipate the power available for the rotation of the motor that operates the flagellum. Below 1 mM, indole did not dissipate the membrane potential. Instead, experiments and modeling indicated that indole weakens cooperative protein interactions within the flagellar complexes to inhibit motility. The metabolite also induced reversals in the rotational direction of the motor to promote a weak chemotactic response, even when the chemotaxis response regulator, CheY, was lacking. Experiments further revealed that indole does not require the transporter Mtr to cross the membrane and influence motor functions. Based on these findings, we propose that indole modulates intra- and inter-protein interactions in the cell to influence several physiological functions.
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Affiliation(s)
- Rachit Gupta
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA
| | - Kathy Y Rhee
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA
| | - Sarah D Beagle
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, 63130, USA
| | - Ravi Chawla
- Department of Integrative Structural and Computational Biology, Scripps Research, La Jolla, CA 92037, USA
| | - Nicolas Perdomo
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA
| | - Steve W Lockless
- Department of Biology, Texas A&M University, College Station, TX 77843-3258, USA
| | - Pushkar P Lele
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA
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6
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Wheatley P, Gupta S, Pandini A, Chen Y, Petzold CJ, Ralston CY, Blair DF, Khan S. Allosteric Priming of E. coli CheY by the Flagellar Motor Protein FliM. Biophys J 2020; 119:1108-1122. [PMID: 32891187 DOI: 10.1016/j.bpj.2020.08.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 07/22/2020] [Accepted: 08/10/2020] [Indexed: 02/07/2023] Open
Abstract
Phosphorylation of Escherichia coli CheY protein transduces chemoreceptor stimulation to a highly cooperative flagellar motor response. CheY binds to the N-terminal peptide of the FliM motor protein (FliMN). Constitutively active D13K-Y106W CheY has been an important tool for motor physiology. The crystal structures of CheY and CheY ⋅ FliMN with and without D13K-Y106W have shown FliMN-bound CheY contains features of both active and inactive states. We used molecular dynamics (MD) simulations to characterize the CheY conformational landscape accessed by FliMN and D13K-Y106W. Mutual information measures identified the central features of the long-range CheY allosteric network between D57 phosphorylation site and the FliMN interface, namely the closure of the α4-β4 hinge and inward rotation of Y- or W106 with W58. We used hydroxy-radical foot printing with mass spectroscopy (XFMS) to track the solvent accessibility of these and other side chains. The solution XFMS oxidation rate correlated with the solvent-accessible area of the crystal structures. The protection of allosteric relay side chains reported by XFMS confirmed the intermediate conformation of the native CheY ⋅ FliMN complex, the inactive state of free D13K-Y106W CheY, and the MD-based network architecture. We extended the MD analysis to determine temporal coupling and energetics during activation. Coupled aromatic residue rotation was a graded rather than a binary switch, with Y- or W106 side-chain burial correlated with increased FliMN affinity. Activation entrained CheY fold stabilization to FliMN affinity. The CheY network could be partitioned into four dynamically coordinated sectors. Residue substitutions mapped to sectors around D57 or the FliMN interface according to phenotype. FliMN increased sector size and interactions. These sectors fused between the substituted K13-W106 residues to organize a tightly packed core and novel surfaces that may bind additional sites to explain the cooperative motor response. The community maps provide a more complete description of CheY priming than proposed thus far.
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Affiliation(s)
- Paige Wheatley
- Department of Biology, University of Utah, Salt Lake City, Utah
| | - Sayan Gupta
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California
| | - Alessandro Pandini
- Department of Computer Science-Synthetic Biology Theme, Brunel University London, Uxbridge, United Kingdom; Computational Cell and Molecular Biology, the Francis Crick Institute, London, United Kingdom
| | - Yan Chen
- Biological Systems and Engineering, Lawrence, Lawrence Berkeley National Laboratory, Berkeley, California
| | - Christopher J Petzold
- Biological Systems and Engineering, Lawrence, Lawrence Berkeley National Laboratory, Berkeley, California
| | - Corie Y Ralston
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California
| | - David F Blair
- Department of Biology, University of Utah, Salt Lake City, Utah
| | - Shahid Khan
- Computational Cell and Molecular Biology, the Francis Crick Institute, London, United Kingdom; Molecular Biology Consortium, Lawrence Berkeley National Laboratory, Berkeley, California.
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7
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Carroll BL, Nishikino T, Guo W, Zhu S, Kojima S, Homma M, Liu J. The flagellar motor of Vibrio alginolyticus undergoes major structural remodeling during rotational switching. eLife 2020; 9:61446. [PMID: 32893817 PMCID: PMC7505661 DOI: 10.7554/elife.61446] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 09/04/2020] [Indexed: 11/26/2022] Open
Abstract
The bacterial flagellar motor switches rotational direction between counterclockwise (CCW) and clockwise (CW) to direct the migration of the cell. The cytoplasmic ring (C-ring) of the motor, which is composed of FliG, FliM, and FliN, is known for controlling the rotational sense of the flagellum. However, the mechanism underlying rotational switching remains elusive. Here, we deployed cryo-electron tomography to visualize the C-ring in two rotational biased mutants in Vibrio alginolyticus. We determined the C-ring molecular architectures, providing novel insights into the mechanism of rotational switching. We report that the C-ring maintained 34-fold symmetry in both rotational senses, and the protein composition remained constant. The two structures show FliG conformational changes elicit a large conformational rearrangement of the rotor complex that coincides with rotational switching of the flagellum. FliM and FliN form a stable spiral-shaped base of the C-ring, likely stabilizing the C-ring during the conformational remodeling.
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Affiliation(s)
- Brittany L Carroll
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, United States.,Microbial Sciences Institute, Yale University, West Haven, United States
| | - Tatsuro Nishikino
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan
| | - Wangbiao Guo
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, United States.,Microbial Sciences Institute, Yale University, West Haven, United States
| | - Shiwei Zhu
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, United States.,Microbial Sciences Institute, Yale University, West Haven, United States
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, United States.,Microbial Sciences Institute, Yale University, West Haven, United States
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8
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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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9
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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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10
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Abstract
Classically, phenotype is what is observed, and genotype is the genetic makeup. Statistical studies aim to project phenotypic likelihoods of genotypic patterns. The traditional genotype-to-phenotype theory embraces the view that the encoded protein shape together with gene expression level largely determines the resulting phenotypic trait. Here, we point out that the molecular biology revolution at the turn of the century explained that the gene encodes not one but ensembles of conformations, which in turn spell all possible gene-associated phenotypes. The significance of a dynamic ensemble view is in understanding the linkage between genetic change and the gained observable physical or biochemical characteristics. Thus, despite the transformative shift in our understanding of the basis of protein structure and function, the literature still commonly relates to the classical genotype-phenotype paradigm. This is important because an ensemble view clarifies how even seemingly small genetic alterations can lead to pleiotropic traits in adaptive evolution and in disease, why cellular pathways can be modified in monogenic and polygenic traits, and how the environment may tweak protein function.
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Affiliation(s)
- Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland, United States of America
- Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Chung-Jung Tsai
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland, United States of America
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland, United States of America
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11
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Conformational coupling by trans-phosphorylation in calcium calmodulin dependent kinase II. PLoS Comput Biol 2019; 15:e1006796. [PMID: 31150387 PMCID: PMC6576796 DOI: 10.1371/journal.pcbi.1006796] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 06/17/2019] [Accepted: 03/28/2019] [Indexed: 12/16/2022] Open
Abstract
The calcium calmodulin-dependent protein kinase II (CaMKII) is a dodecameric holoenzyme important for encoding memory. Its activation, triggered by binding of calcium-calmodulin, persists autonomously after calmodulin dissociation. One (receiver) kinase captures and subsequently phosphorylates the regulatory domain peptide of a donor kinase forming a chained dimer as the first stage of autonomous activation. Protein dynamics simulations examined the conformational changes triggered by dimer formation and phosphorylation, aimed to provide a molecular rationale for human mutations that result in learning disabilities. Ensembles generated from X-ray crystal structures were characterized by network centrality and community analysis. Mutual information related collective motions to local fragment dynamics encoded with a structural alphabet. Implicit solvent tCONCOORD conformational ensembles revealed the dynamic architecture of inactive kinase domains was co-opted in the activated dimer but the network hub shifted from the nucleotide binding cleft to the captured peptide. Explicit solvent molecular dynamics (MD) showed nucleotide and substrate binding determinants formed coupled nodes in long-range signal relays between regulatory peptides in the dimer. Strain in the extended captured peptide was balanced by reduced flexibility of the receiver kinase C-lobe core. The relays were organized around a hydrophobic patch between the captured peptide and a key binding helix. The human mutations aligned along the relays. Thus, these mutations could disrupt the allosteric network alternatively, or in addition, to altered binding affinities. Non-binding protein sectors distant from the binding sites mediated the allosteric signalling; providing possible targets for inhibitor design. Phosphorylation of the peptide modulated the dielectric of its binding pocket to strengthen the patch, non-binding sectors, domain interface and temporal correlations between parallel relays. These results provide the molecular details underlying the reported positive kinase cooperativity to enrich the discussion on how autonomous activation by phosphorylation leads to long-term behavioural effects. Protein kinases play central roles in intracellular signalling. Auto-phosphorylation by bound nucleotide typically precedes phosphate transfer to multiple substrates. Protein conformational changes are central to kinase function, altering binding affinities to change cellular location and shunt from one signal pathway to another. In the brain, the multi-subunit kinase, CaMKII is activated by calcium-calmodulin upon calcium jumps produced by synaptic stimulation. Auto-transphosphorylation of a regulatory peptide enables the kinase to remain activated and mediate long-term behavioural effects after return to basal calcium levels. A database of mutated residues responsible for these effects is difficult to reconcile solely with impaired nucleotide or substrate binding. Therefore, we have computationally generated interaction networks to map the conformational plasticity of the kinase domains where most mutations localize. The network generated from the atomic structure of a phosphorylated dimer resolves protein sectors based on their collective motions. The sectors link nucleotide and substrate binding sites in self-reinforcing relays between regulatory peptides. The self-reinforcement is strengthened by phosphorylation consistent with the reported positive cooperativity of kinase activity with calcium-calmodulin concentration. The network gives a better match with the mutations and, in addition, reveals target sites for drug development.
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12
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The role of coevolutionary signatures in protein interaction dynamics, complex inference, molecular recognition, and mutational landscapes. Curr Opin Struct Biol 2019; 56:179-186. [PMID: 31029927 DOI: 10.1016/j.sbi.2019.03.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 03/18/2019] [Accepted: 03/19/2019] [Indexed: 11/22/2022]
Abstract
Evolution imposes constraints at the interface of interacting biomolecules in order to preserve function or maintain fitness. This pressure may have a direct effect on the sequence composition of interacting biomolecules. As a result, statistical patterns of amino acid or nucleotide covariance that encode for physical and functional interactions are observed in sequences of extant organisms. In recent years, global pairwise models of amino acid and nucleotide coevolution from multiple sequence alignments have been developed and utilized to study molecular interactions in structural biology. In proteins, for which the energy landscape is funneled and minimally frustrated, a direct connection between the physical and sequence space landscapes can be established. Estimating coevolutionary information from sequences of interacting molecules has a broad impact in molecular biology. Applications include the accurate determination of 3D structures of molecular complexes, inference of protein interaction partners, models of protein-protein interaction specificity, the elucidation, and design of protein-nucleic acid recognition as well as the discovery of genome-wide epistatic effects. The current state of the art of coevolutionary analysis includes biomedical applications ranging from mutational landscapes and drug-design to vaccine development.
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13
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Abstract
Thanks to the explosion of genomic sequencing, coevolutionary analysis of protein sequences has gained great and ever-increasing popularity in the last decade, and it is currently an important and well-established tool in structural bioinformatics and computational biology. This chapter concisely introduces the theoretical foundation and the practical aspects of coevolutionary analysis, as well as discusses the molecular modeling strategies to exploit its results in the study of protein structure, dynamics, and interactions. We present here a complete pipeline from sequence extraction to contact prediction through two examples, focusing on the predictions of inter-residue contacts in a single protein domain and on the analysis of a multi-domain protein that undergoes functional, large-scale conformational transitions.
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Affiliation(s)
- Duccio Malinverni
- Laboratory of Statistical Biophysics, Institute of Physics, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | - Alessandro Barducci
- Centre de Biochimie Structurale (CBS), INSERM, CNRS, Université de Montpellier, Montpellier, France.
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14
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Rotational direction of flagellar motor from the conformation of FliG middle domain in marine Vibrio. Sci Rep 2018; 8:17793. [PMID: 30542147 PMCID: PMC6290876 DOI: 10.1038/s41598-018-35902-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 11/08/2018] [Indexed: 12/14/2022] Open
Abstract
FliG, which is composed of three distinctive domains, N-terminal (N), middle (M), and C-terminal (C), is an essential rotor component that generates torque and determines rotational direction. To determine the role of FliG in determining flagellar rotational direction, we prepared rotational biased mutants of fliG in Vibrio alginolyticus. The E144D mutant, whose residue is belonging to the EHPQR-motif in FliGM, exhibited an increased number of switching events. This phenotype generated a response similar to the phenol-repellent response in chemotaxis. To clarify the effect of E144D mutation on the rotational switching, we combined the mutation with other che mutations (G214S, G215A and A282T) in FliG. Two of the double mutants suppressed the rotational biased phenotype. To gain structural insight into the mutations, we performed molecular dynamic simulations of the FliGMC domain, based on the crystal structure of Thermotoga maritima FliG and nuclear magnetic resonance analysis. Furthermore, we examined the swimming behavior of the fliG mutants lacking CheY. The results suggested that the conformation of FliG in E144D mutant was similar to that in the wild type. However, that of G214S and G215A caused a steric hindrance in FliG. The conformational change in FliGM triggered by binding CheY may lead to a rapid change of direction and may occur in both directional states.
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15
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Ford KM, Antani JD, Nagarajan A, Johnson MM, Lele PP. Switching and Torque Generation in Swarming E. coli. Front Microbiol 2018; 9:2197. [PMID: 30279682 PMCID: PMC6153309 DOI: 10.3389/fmicb.2018.02197] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 08/28/2018] [Indexed: 12/14/2022] Open
Abstract
Escherichia coli swarm on semi-solid surfaces with the aid of flagella. It has been hypothesized that swarmer cells overcome the increased viscous drag near surfaces by developing higher flagellar thrust and by promoting surface wetness with the aid of a flagellar switch. The switch enables reversals between clockwise (CW) and counterclockwise (CCW) directions of rotation of the flagellar motor. Here, we measured the behavior of flagellar motors in swarmer cells. Results indicated that although the torque was similar to that in planktonic cells, the tendency to rotate CCW was higher in swarmer cells. This suggested that swarmers likely have a smaller pool of phosphorylated CheY. Results further indicated that the upregulation of the flagellin gene was not critical for flagellar thrust or swarming. Consistent with earlier reports, moisture added to the swarm surface restored swarming in a CCW-only mutant, but not in a FliG mutant that rotated motors CW-only (FliGCW). Fluorescence assays revealed that FliGCW cells grown on agar surfaces carried fewer flagella than planktonic FliGCW cells. The surface-dependent reduction in flagella correlated with a reduction in the number of putative flagellar preassemblies. These results hint toward a possibility that the conformational dynamics of switch proteins play a role in the proper assembly of flagellar complexes and flagellar export, thereby aiding bacterial swarming.
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Affiliation(s)
- Katie M Ford
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, United States
| | - Jyot D Antani
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, United States
| | - Aravindh Nagarajan
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, United States
| | - Madeline M Johnson
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, United States
| | - Pushkar P Lele
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, United States
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16
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Khan S, Guo TW, Misra S. A coevolution-guided model for the rotor of the bacterial flagellar motor. Sci Rep 2018; 8:11754. [PMID: 30082903 PMCID: PMC6079021 DOI: 10.1038/s41598-018-30293-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/19/2018] [Indexed: 01/17/2023] Open
Abstract
The Salmonella typhimurium trans-membrane FliF MS ring templates assembly of the rotary bacterial flagellar motor, which also contains a cytoplasmic C-ring. A full-frame fusion of FliF with the rotor protein FliG assembles rings in non-motile expression hosts. 3D electron microscopy reconstructions of these FliFFliG rings show three high electron-density sub-volumes. 3D-classification revealed heterogeneity of the assigned cytoplasmic volume consistent with FliG lability. We used residue coevolution to construct homodimer building blocks for ring assembly, with X-ray crystal structures from other species and injectisome analogs. The coevolution signal validates folds and, importantly, indicates strong homodimer contacts for three ring building motifs (RBMs), initially identified in injectisome structures. It also indicates that the cofolded domains of the FliG N-terminal domain (FliG_N) with embedded α-helical FliF carboxy-terminal tail homo-oligomerize. The FliG middle and C-terminal domains (FliG_MC) have a weak signal for homo-dimerization but have coevolved to conserve their stacking contact. The homodimers and their ring models fit well into the 3D reconstruction. We hypothesize that a stable FliF periplasmic hub provides a platform for FliG ring self-assembly, but the FliG_MC ring has only limited stability without the C-ring. We also present a mechanical model for torque transmission in the FliFFliG ring.
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Affiliation(s)
- Shahid Khan
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA.
- Molecular Biology Consortium, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Tai Wei Guo
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Saurav Misra
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
- Department of Biochemistry & Molecular Biophysics, Kansas State University, Manhattan, KS, 66506, USA
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17
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dos Santos RN, Khan S, Morcos F. Characterization of C-ring component assembly in flagellar motors from amino acid coevolution. ROYAL SOCIETY OPEN SCIENCE 2018; 5:171854. [PMID: 29892378 PMCID: PMC5990795 DOI: 10.1098/rsos.171854] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Accepted: 04/05/2018] [Indexed: 06/08/2023]
Abstract
Bacterial flagellar motility, an important virulence factor, is energized by a rotary motor localized within the flagellar basal body. The rotor module consists of a large framework (the C-ring), composed of the FliG, FliM and FliN proteins. FliN and FliM contacts the FliG torque ring to control the direction of flagellar rotation. We report that structure-based models constrained only by residue coevolution can recover the binding interface of atomic X-ray dimer complexes with remarkable accuracy (approx. 1 Å RMSD). We propose a model for FliM-FliN heterodimerization, which agrees accurately with homologous interfaces as well as in situ cross-linking experiments, and hence supports a proposed architecture for the lower portion of the C-ring. Furthermore, this approach allowed the identification of two discrete and interchangeable homodimerization interfaces between FliM middle domains that agree with experimental measurements and might be associated with C-ring directional switching dynamics triggered upon binding of CheY signal protein. Our findings provide structural details of complex formation at the C-ring that have been difficult to obtain with previous methodologies and clarify the architectural principle that underpins the ultra-sensitive allostery exhibited by this ring assembly that controls the clockwise or counterclockwise rotation of flagella.
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Affiliation(s)
- Ricardo Nascimento dos Santos
- Institute of Chemistry and Center for Computational Engineering and Science, University of Campinas, Campinas, SP, Brazil
| | - Shahid Khan
- Molecular Biology Consortium, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Faruck Morcos
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX, USA
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, USA
- Center for Systems Biology, University of Texas at Dallas, Richardson, TX, USA
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18
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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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19
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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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20
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Wang F, Burrage AM, Postel S, Clark RE, Orlova A, Sundberg EJ, Kearns DB, Egelman EH. A structural model of flagellar filament switching across multiple bacterial species. Nat Commun 2017; 8:960. [PMID: 29038601 PMCID: PMC5643327 DOI: 10.1038/s41467-017-01075-5] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 08/15/2017] [Indexed: 12/21/2022] Open
Abstract
The bacterial flagellar filament has long been studied to understand how a polymer composed of a single protein can switch between different supercoiled states with high cooperativity. Here we present near-atomic resolution cryo-EM structures for flagellar filaments from both Gram-positive Bacillus subtilis and Gram-negative Pseudomonas aeruginosa. Seven mutant flagellar filaments in B. subtilis and two in P. aeruginosa capture two different states of the filament. These reliable atomic models of both states reveal conserved molecular interactions in the interior of the filament among B. subtilis, P. aeruginosa and Salmonella enterica. Using the detailed information about the molecular interactions in two filament states, we successfully predict point mutations that shift the equilibrium between those two states. Further, we observe the dimerization of P. aeruginosa outer domains without any perturbation of the conserved interior of the filament. Our results give new insights into how the flagellin sequence has been "tuned" over evolution.Bacterial flagellar filaments are composed almost entirely of a single protein-flagellin-which can switch between different supercoiled states in a highly cooperative manner. Here the authors present near-atomic resolution cryo-EM structures of nine flagellar filaments, and begin to shed light on the molecular basis of filament switching.
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Affiliation(s)
- Fengbin Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Andrew M Burrage
- Department of Biology, Indiana University, Bloomington, IN, 47305, USA
| | - Sandra Postel
- Institute of Human Virology and University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Reece E Clark
- Department of Biology, Indiana University, Bloomington, IN, 47305, USA
| | - Albina Orlova
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Eric J Sundberg
- Institute of Human Virology and University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Departments of Medicine and of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, 21201, MD, USA
| | - Daniel B Kearns
- Department of Biology, Indiana University, Bloomington, IN, 47305, USA
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.
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21
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Choi MK, Jo S, Lee BH, Kim MH, Choi JB, Kim K, Kim MK. Dynamic characteristics of a flagellar motor protein analyzed using an elastic network model. J Mol Graph Model 2017; 78:81-87. [PMID: 29054097 DOI: 10.1016/j.jmgm.2017.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 10/02/2017] [Accepted: 10/03/2017] [Indexed: 12/23/2022]
Abstract
At the base of a flagellar motor, its rotational direction and speed are regulated by the interaction between rotor and stator proteins. A switching event occurs when the cytoplasmic rotor protein, called C-ring, changes its conformation in response to binding of the CheY signal protein. The C-ring structure consists of FliG, FliM, and FliN proteins and its conformational changes in FliM and FliG including HelixMC play an important role in switching the motor direction. Therefore, clarifying their dynamic properties as well as conformational changes is a key to understanding the switching mechanism of the motor protein. In this study, to elucidate dynamic characteristics of the C-ring structure, both harmonic (intrinsic vibration) and anharmonic (transition pathway) analyses are conducted by using the symmetry-constrained elastic network model. As a result, the first three normal modes successfully capture the essence of transition pathway from wild type to CW-biased state. Their cumulative square overlap value reaches up to 0.842. Remarkably, it is also noted from the transition pathway that the cascade of interactions from the signal protein to FliM to FliG, highlighted by the major mode shapes from the first three normal modes, induces the reorientation (∼100° rotation of FliGC5) of FliG C-terminal that directly interacts with the stator protein. Presumably, the rotational direction of the motor protein is switched by this substantial change in the stator-rotor interaction.
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Affiliation(s)
- Moon-Ki Choi
- School of Mechanical Engineering, Sungkyunkwan University, Suwon, 16419, Korea
| | - Soojin Jo
- School of Mechanical Engineering, Sungkyunkwan University, Suwon, 16419, Korea
| | - Byung Ho Lee
- School of Mechanical Engineering, Sungkyunkwan University, Suwon, 16419, Korea
| | - Min Hyeok Kim
- Korea Institute for Advanced Study, Seoul, 02455, Korea
| | - Jae Boong Choi
- School of Mechanical Engineering, Sungkyunkwan University, Suwon, 16419, Korea
| | - Kyunghoon Kim
- School of Mechanical Engineering, Sungkyunkwan University, Suwon, 16419, Korea
| | - Moon Ki Kim
- School of Mechanical Engineering, Sungkyunkwan University, Suwon, 16419, Korea.
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22
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Structural and Functional Analysis of the C-Terminal Region of FliG, an Essential Motor Component of Vibrio Na+-Driven Flagella. Structure 2017; 25:1540-1548.e3. [DOI: 10.1016/j.str.2017.08.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 07/15/2017] [Accepted: 08/15/2017] [Indexed: 01/24/2023]
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23
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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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24
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Kim EA, Panushka J, Meyer T, Carlisle R, Baker S, Ide N, Lynch M, Crane BR, Blair DF. Architecture of the Flagellar Switch Complex of Escherichia coli: Conformational Plasticity of FliG and Implications for Adaptive Remodeling. J Mol Biol 2017; 429:1305-1320. [PMID: 28259628 PMCID: PMC5494207 DOI: 10.1016/j.jmb.2017.02.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/16/2017] [Accepted: 02/16/2017] [Indexed: 12/29/2022]
Abstract
Structural models of the complex that regulates the direction of flagellar rotation assume either ~34 or ~25 copies of the protein FliG. Support for ~34 came from crosslinking experiments identifying an intersubunit contact most consistent with that number; support for ~25 came from the observation that flagella can assemble and rotate when FliG is genetically fused to FliF, for which the accepted number is ~25. Here, we have undertaken crosslinking and other experiments to address more fully the question of FliG number. The results indicate a copy number of ~25 for FliG. An interaction between the C-terminal and middle domains, which has been taken to support a model with ~34 copies, is also supported. To reconcile the interaction with a FliG number of ~25, we hypothesize conformational plasticity in an interdomain segment of FliG that allows some subunits to bridge gaps created by the number mismatch. This proposal is supported by mutant phenotypes and other results indicating that the normally helical segment adopts a more extended conformation in some subunits. The FliG amino-terminal domain is organized in a regular array with dimensions matching a ring in the upper part of the complex. The model predicts that FliG copy number should be tied to that of FliF, whereas FliM copy number can increase or decrease according to the number of FliG subunits that adopt the extended conformation. This has implications for the phenomenon of adaptive switch remodeling, in which the FliM copy number varies to adjust the bias of the switch.
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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
| | - 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
| | - Nicholas Ide
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Michael Lynch
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Brian R Crane
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - David F Blair
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA.
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