Encyclopedia of Biophysics

Living Edition
| Editors: Gordon Roberts, Anthony Watts, European Biophysical Societies

Electron Microscopy of Motor Structure and Possible Mechanisms

  • Tohru Minamino
  • Takayuki Kato
  • Fumiaki Makino
  • Péter Horváth
  • Tomoko Miyata
  • Keiichi Namba
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-35943-9_196-1



Structural analyses of substructures of the bacterial flagellum by the complementary use of cryoelectron microscopy and X-ray crystallography provide structural and mechanical insights into the mechanisms of how they can exert their functions.


The bacterial flagellum is supramolecular motility machinery consisting at least of three parts: the basal body, the hook, and the filament. Flagellar assembly begins with the basal body, followed by the hook, and finally the filament. Most flagellar proteins are translocated via a type III protein export apparatus into the central channel of the growing flagellar structure and assemble at the distal end of the structure with the help of a capping structure. Escherichia coli and Salmonella entericaare model organisms that have provided detailed insights into the structure, assembly, and function of the...

This is a preview of subscription content, log in to check access.


  1. Abrusci P, Vergara-Irigaray M, Johnson S, Beeby MD, Hendrixson DR, Roversi P, Friede ME, Deane JE, Jensen GJ, Tang CM, Lea SM (2013) Architecture of the major component of the type III secretion system export apparatus. Nat Struct Mol Biol 20:99–104CrossRefPubMedGoogle Scholar
  2. Bai F, Morimoto YV, Yoshimura SDJ, Hara N, Kami-ike N, Namba K, Minamino T (2014) Assembly dynamics and the roles of FliI ATPase of the bacterial flagellar export apparatus. Sci Rep 4:6528CrossRefPubMedPubMedCentralGoogle Scholar
  3. Branch RW, Sayegh MN, Shen C, Nathan VS, Berg HC (2014) Adaptive remodeling by FliN in the bacterial rotary motor. J Mol Biol 426:3314–3324CrossRefPubMedPubMedCentralGoogle Scholar
  4. Castillo DJ, Nakamura S, Morimoto YV, Che Y-S, Kamiike N, Kudo S, Minamino T, Namba K (2013) The C-terminal periplasmic domain of MotB is responsible for load-dependent control of the number of stators of the bacterial flagellar motor. Biophysics 9:173–181CrossRefPubMedPubMedCentralGoogle Scholar
  5. Fujii T, Kato T, Namba K (2009) Specific arrangement of α-helical coiled coils in the core domain of the bacterial flagellar hook for the universal joint function. Structure 17:1485–1493CrossRefPubMedGoogle Scholar
  6. Fujii T, Kato T, Hiraoka D, Miyata T, Minamino T, Chevance F, Hughes K, Namba K (2017) Identical folds used for distinct mechanical functions of the bacterial flagellar rod and hook. Nat Commun 8:14276CrossRefPubMedPubMedCentralGoogle Scholar
  7. Fukumura T, Makino F, Dietsche T, Kinoshita M, Kato T, Wagner S, Namba K, Imada K, Minamino T (2017) Assembly and stoichiometry of the core structure of the bacterial flagellar type III export gate complex. PLoS Biol 15:e2002281CrossRefPubMedPubMedCentralGoogle Scholar
  8. Hiraoka KD, Morimoto YV, Inoue Y, Fujii T, Miyata T, Makino F, Minamino T, Namba K (2017) Straight and rigid flagellar hook made by insertion of the FlgG specific sequence into FlgE. Sci Rep 7:46723CrossRefPubMedPubMedCentralGoogle Scholar
  9. Ibuki T, Imada K, Minamino T, Kato T, Miyata T, Namba K (2011) Common architecture between the flagellar protein export apparatus and F- and V-ATPases. Nat Struct Mol Biol 18:277–282CrossRefPubMedGoogle Scholar
  10. Imada K, Minamino T, Kinoshita M, Furukawa Y, Namba K (2010) Structural insight into the regulatory mechanisms of interactions of the flagellar type III chaperone FliT with its binding partners. Proc Natl Acad Sci U S A 107:8812–8817CrossRefPubMedPubMedCentralGoogle Scholar
  11. Imada K, Minamino T, Uchida Y, Kinoshita M, Namba K (2016) Insight into the flagella type III export revealed by the complex structure of the type III ATPase and its regulator. Proc Natl Acad Sci U S A 113:3633–3638CrossRefPubMedPubMedCentralGoogle Scholar
  12. Kato S, Okamoto M, Asakura S (1984) Polymorphic transformation of the flagellar polyhook from Escherichia coli and Salmonella typhimurium. J Mol Biol 173:463–476CrossRefPubMedGoogle Scholar
  13. Kawamoto A, Morimoto YV, Miyata T, Minamino T, Hughes KT, Namba K (2013) Common and distinct structural features of Salmonella injectisome and flagellar basal body. Sci Rep 3:3369CrossRefPubMedPubMedCentralGoogle Scholar
  14. Leake MC, Chandler JH, Wadhams GH, Bai F, Berry RM, Armitage JP (2006) Stoichiometry and turnover in single, functioning membrane protein complexes. Nature 443:355–358CrossRefPubMedGoogle Scholar
  15. Lele PP, Hosu BG, Berg HC (2013) Dynamics of mechanosensing in the bacterial flagellar motor. Proc Natl Acad Sci U S A 110:11839–11844CrossRefPubMedPubMedCentralGoogle Scholar
  16. Maki-Yonekura S, Yonekura K, Namba K (2010) Conformational change of flagellin for polymorphic supercoiling of the flagellar filament. Nat Struct Mol Biol 17:417–422CrossRefPubMedGoogle Scholar
  17. Matsunami H, Barker CS, Yoon YH, Wolf M, Samatey FA (2016a) Complete structureof the bacterial hook reveals extensive set of stabilizing interactions. Nat Commun 7:13425CrossRefPubMedPubMedCentralGoogle Scholar
  18. Matsunami H, Yoon YH, Meshcheryakov VA, Namba K, Samatey FA (2016b) Structural flexibility of the periplasmic protein, FlgA, regulates flagellar P-ring assembly in Salmonella enterica. Sci Rep 6:27399CrossRefPubMedPubMedCentralGoogle Scholar
  19. Minamino T, Imada K (2015) The bacterial flagellar motor and its structural diversity. Trends Microbiol 23:267–274CrossRefPubMedGoogle Scholar
  20. Minamino T, Yamaguchi S, Macnab RM (2000) Interaction between FliE and FlgB, a proximal rod component of the flagellar basal body of Salmonella. J Bacteriol 182:3029–3036CrossRefPubMedPubMedCentralGoogle Scholar
  21. Minamino T, Morimoto YV, Hara N, Namba K (2011) An energy transduction mechanism used in bacterial type III protein export. Nat Commun 2:475CrossRefPubMedPubMedCentralGoogle Scholar
  22. Morimoto YV, Nakamura S, Hiraoka KD, Namba K, Minamino T (2013) Distinct roles of highly conserved charged residues at the MotA-FliG interface in bacterial flagellar motor rotation. J Bacteriol 195:474–481CrossRefPubMedPubMedCentralGoogle Scholar
  23. Moriya N, Minamino T, Imada K, Namba K (2011) Genetic analysis of the bacterial hook-capping protein responsible for hook assembly. Microbiology 157:1354–1362CrossRefPubMedGoogle Scholar
  24. Postel S, Deredge D, Bonsor DA, Yu X, Diederichs K, Helmsing S, Vromen A, Friedler A, Hust M, Egelman EH, Beckett D, Wintrode PL, Sundberg EJ (2016) Bacterial flagellar capping proteins adopts diverse oligomeric states. elife 5:e18857CrossRefPubMedPubMedCentralGoogle Scholar
  25. Samatey FA, Matsunami H, Imada K, Nagashima S, Shaikh TR, Thomas DR, Chen JZ, DeRosier DJ, Kitao A, Namba K (2004) Structure of the bacterial flagellar hook and implication for the molecular universal joint mechanism. Nature 431:1062–1068CrossRefPubMedGoogle Scholar
  26. Song WS, Cho SY, Hong HJ, Park SC, Yoon SI (2017) Self-oligomerizing structure of the flagellar cap protein FliD and its implication in filament assembly. J Mol Biol 429:847–857CrossRefPubMedGoogle Scholar
  27. Takekawa N, Terahara N, Kato T, Gohara M, Mayanagi K, Hijikata A, Onoue T, Kojima S, Shirai T, Namba K, Homma M (2016) The tetrameric MotA complex as the core of the flagellar motor stator from hyperthermophilic bacterium. Sci Rep 6:31526CrossRefPubMedPubMedCentralGoogle Scholar
  28. Terahara N, Noguchi Y, Nakamura S, Kami-ike N, Ito M, Namba K, Minamino T (2017) Load- and polysaccharide-dependent activation of the Na+-type MotPS stator in the Bacillus subtilis flagellar motor. Sci Rep 7:46081CrossRefPubMedPubMedCentralGoogle Scholar
  29. Yonekura K, Maki S, Morgan DG, DeRosier DJ, Vonderviszt F, Imada K, Namba K (2000) The bacterial flagellar cap as the rotary promoter of flagellin self-assembly. Science 290:2148–2152CrossRefPubMedGoogle Scholar
  30. Yonekura K, Maki-Yonekura S, Namba K (2003) Complete atomic model of the bacterial flagellar filament by electron cryomicroscopy. Nature 424:643–650CrossRefPubMedGoogle Scholar
  31. Yuan J, Berg HC (2013) Ultrasensitivity of an adaptive bacterial motor. J Mol Biol 425:1760–1764CrossRefPubMedGoogle Scholar
  32. Yuan J, Branch RW, Hosu BG, Berg HC (2012) Adaptation at the output of the chemotaxis signalling pathway. Nature 484:233–236CrossRefPubMedPubMedCentralGoogle Scholar
  33. Zhou J, Lloyd SA, Blair DF (1998) Electrostatic interactions between rotor and stator in the bacterial flagellar motor. Proc Natl Acad Sci U S A 95:6436–6441CrossRefPubMedPubMedCentralGoogle Scholar

Copyright information

© European Biophysical Societies' Association (EBSA) 2018

Authors and Affiliations

  • Tohru Minamino
    • 1
  • Takayuki Kato
    • 1
  • Fumiaki Makino
    • 1
  • Péter Horváth
    • 1
  • Tomoko Miyata
    • 1
  • Keiichi Namba
    • 1
  1. 1.Graduate School of Frontier BiosciencesOsaka UniversityOsakaJapan

Section editors and affiliations

  • Judith P. Armitage
    • 1
  1. 1.OCISB, Department of BiochemistryUniversity of OxfordOxfordUK