Encyclopedia of Biophysics

2013 Edition
| Editors: Gordon C. K. Roberts

Flagellar Motor: Molecular Architecture In Situ

  • Jun LiuEmail author
  • Xiaowei Zhao
  • Steven J. Norris
Reference work entry
DOI: https://doi.org/10.1007/978-3-642-16712-6_201



Bacterial flagellae are helical filaments propelled by rotary motors, remarkable nanomachines embedded in the bacterial cell envelope. Powered by a proton or sodium gradient across the cytoplasmic membrane, the flagellar motor converts electrochemical energy into torque by interacting with the stator, a surrounding protein assembly embedded in the cytoplasmic membrane. Of the approximately 50 genes involved in the expression and assembly of the flagellum, about 20 produce protein components of the flagellar motor. The process of flagellar assembly is well understood from extensive studies on assembly-defective mutants in two model systems Salmonella enterica and Escherichia coli. Structural studies have also revealed the molecular architecture of the rotor in great detail. However, the mechanism of flagellar rotation remains poorly understood at the molecular level, mainly because of the lack of structural information about the intact flagellar...

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  1. Al-Amoudi A, Chang JJ, et al. Cryo-electron microscopy of vitreous sections. EMBO J. 2004;23(18):3583–8.PubMedGoogle Scholar
  2. Baumeister W, Grimm R, et al. Electron tomography of molecules and cells. Trends Cell Biol. 1999;9(2):81–5.PubMedGoogle Scholar
  3. Berg HC. The rotary motor of bacterial flagella. Annu Rev Biochem. 2003;72:19–54.PubMedGoogle Scholar
  4. Berg HC. E. coli in motion. New York: Springer; 2004.Google Scholar
  5. Charon NW, Goldstein SF. Genetics of motility and chemotaxis of a fascinating group of bacteria: the spirochetes. Annu Rev Genet. 2002;36:47–73.PubMedGoogle Scholar
  6. Dubochet J, Adrian M, et al. Cryo-electron microscopy of vitrified specimens. Q Rev Biophys. 1988;21(2):129–228.PubMedGoogle Scholar
  7. Frank J. Electron tomography: methods for three-dimensional visualization of structures in the cell. New York/London: Springer; 2006.Google Scholar
  8. Jarrell KF, McBride MJ. The surprisingly diverse ways that prokaryotes move. Nat Rev Microbiol. 2008;6(6):466–76.PubMedGoogle Scholar
  9. Katayama E, Shiraishi T, et al. Geometry of the flagellar motor in the cytoplasmic membrane of Salmonella typhimurium as determined by stereo-photogrammetry of quick-freeze deep-etch replica images. J Mol Biol. 1996;255(3):458–75.PubMedGoogle Scholar
  10. Khan S, Dapice M, et al. Effects of mot gene expression on the structure of the flagellar motor. J Mol Biol. 1988;202(3):575–84.PubMedGoogle Scholar
  11. Koster AJ, Grimm R, et al. Perspectives of molecular and cellular electron tomography. J Struct Biol. 1997;120(3):276–308.PubMedGoogle Scholar
  12. Liu J, Lin T, et al. Intact flagellar motor of Borrelia burgdorferi revealed by cryo-electron tomography: evidence for stator ring curvature and rotor/C-ring assembly flexion. J Bacteriol. 2009;191(16):5026–36.PubMedCentralPubMedGoogle Scholar
  13. Murphy GE, Leadbetter JR, et al. In situ structure of the complete Treponema primitia flagellar motor. Nature. 2006;442(7106):1062–4.PubMedGoogle Scholar
  14. Pallen MJ, Penn CW, et al. Bacterial flagellar diversity in the post-genomic era. Trends Microbiol. 2005;13(4):143–9.PubMedGoogle Scholar
  15. Ren SX, Fu G, et al. Unique physiological and pathogenic features of Leptospira interrogans revealed by whole-genome sequencing. Nature. 2003;422(6934):888–93.PubMedGoogle Scholar
  16. Rendulic S, Jagtap P, et al. A predator unmasked: life cycle of Bdellovibrio bacteriovorus from a genomic perspective. Science. 2004;303(5658):689–92.PubMedGoogle Scholar
  17. Sowa Y, Berry RM. Bacterial flagellar motor. Q Rev Biophys. 2008;41(2):103–32.PubMedGoogle Scholar
  18. Thomas DR, Francis NR, et al. The three-dimensional structure of the flagellar rotor from a clockwise-locked mutant of Salmonella enterica serovar Typhimurium. J Bacteriol. 2006;188(20):7039–48.PubMedCentralPubMedGoogle Scholar

Copyright information

© European Biophysical Societies' Association (EBSA) 2013

Authors and Affiliations

  1. 1.Department of Pathology and Laboratory MedicineUniversity of Texas Health Science Center at HoustonHoustonUSA
  2. 2.Departments of Pathology and Laboratory Medicine and Microbiology and Molecular GeneticsUniversity of Texas Health Science Center at HoustonHoustonUSA