Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Structure of the torque ring of the flagellar motor and the molecular basis for rotational switching

Nature volume 466, pages 996–1000 (2010)Cite this article

Subjects

This article has been updated

Abstract

The flagellar motor drives the rotation of flagellar filaments at hundreds of revolutions per second1,2, efficiently propelling bacteria through viscous media3. The motor uses the potential energy from an electrochemical gradient of cations4,5 across the cytoplasmic membrane to generate torque. A rapid switch from anticlockwise to clockwise rotation determines whether a bacterium runs smoothly forward or tumbles to change its trajectory6,7. A protein called FliG forms a ring in the rotor of the flagellar motor that is involved in the generation of torque8,9,10,11,12,13 through an interaction with the cation-channel-forming stator subunit MotA12. FliG has been suggested to adopt distinct conformations that induce switching but these structural changes and the molecular mechanism of switching are unknown. Here we report the molecular structure of the full-length FliG protein, identify conformational changes that are involved in rotational switching and uncover the structural basis for the formation of the FliG torque ring. This allows us to propose a model of the complete ring and switching mechanism in which conformational changes in FliG reverse the electrostatic charges involved in torque generation.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Structural overview of the full-length FliG monomer.
Figure 2: Conformational differences between A. aeolicus FliGFL and T. maritima FliGMC.
Figure 3: Structural basis for the formation of FliG multimers.
Figure 4: Molecular basis of rotational switching.

Similar content being viewed by others

Accession codes

Primary accessions

Protein Data Bank

Data deposits

The coordinates and structure factors of the A. aeolicus FliG monomer have been deposited in the Protein Data Bank under accession code 3HJL.

Change history

  • 19 August 2010

    Three mistakes were corrected for the print issue.

References

  1. Lowe, G., Meister, M. & Berg, H. C. Rapid rotation of flagellar bundles in swimming bacteria. Nature 325, 637–640 (1987)

    Article  ADS  Google Scholar 

  2. Magariyama, Y. et al. Very fast flagellar rotation. Nature 371, 752 (1994)

    Article  ADS  CAS  Google Scholar 

  3. Berg, H. C. & Anderson, R. A. Bacteria swim by rotating their flagellar filaments. Nature 245, 380–382 (1973)

    Article  ADS  CAS  Google Scholar 

  4. Manson, M. D., Tedesco, P., Berg, H. C., Harold, F. M. & Van der Drift, C. A protonmotive force drives bacterial flagella. Proc. Natl Acad. Sci. USA 74, 3060–3064 (1977)

    Article  ADS  CAS  Google Scholar 

  5. Hirota, N. & Imae, Y. Na+-driven flagellar motors of an alkalophilic Bacillus strain YN-1. J. Biol. Chem. 258, 10577–10581 (1983)

    CAS  PubMed  Google Scholar 

  6. Berg, H. C. & Brown, D. A. Chemotaxis in Escherichia coli analysed by three-dimensional tracking. Nature 239, 500–504 (1972)

    Article  ADS  CAS  Google Scholar 

  7. Turner, L., Ryu, W. S. & Berg, H. C. Real-time imaging of fluorescent flagellar filaments. J. Bacteriol. 182, 2793–2801 (2000)

    Article  CAS  Google Scholar 

  8. Irikura, V. M., Kihara, M., Yamaguchi, S., Sockett, H. & Macnab, R. M. Salmonella typhimurium fliG and fliN mutations causing defects in assembly, rotation, and switching of the flagellar motor. J. Bacteriol. 175, 802–810 (1993)

    Article  CAS  Google Scholar 

  9. Lloyd, S. A. & Blair, D. F. Charged residues of the rotor protein FliG essential for torque generation in the flagellar motor of Escherichia coli. J. Mol. Biol. 266, 733–744 (1997)

    Article  CAS  Google Scholar 

  10. Lloyd, S. A., Tang, H., Wang, X., Billings, S. & Blair, D. F. Torque generation in the flagellar motor of Escherichia coli: evidence of a direct role for FliG but not for FliM or FliN. J. Bacteriol. 178, 223–231 (1996)

    Article  CAS  Google Scholar 

  11. Yorimitsu, T., Mimaki, A., Yakushi, T. & Homma, M. The conserved charged residues of the C-terminal region of FliG, a rotor component of the Na+-driven flagellar motor. J. Mol. Biol. 334, 567–583 (2003)

    Article  CAS  Google Scholar 

  12. Zhou, J., Lloyd, S. A. & Blair, D. F. Electrostatic interactions between rotor and stator in the bacterial flagellar motor. Proc. Natl Acad. Sci. USA 95, 6436–6441 (1998)

    Article  ADS  CAS  Google Scholar 

  13. Lloyd, S. A., Whitby, F. G., Blair, D. F. & Hill, C. P. Structure of the C-terminal domain of FliG, a component of the rotor in the bacterial flagellar motor. Nature 400, 472–475 (1999)

    Article  ADS  CAS  Google Scholar 

  14. Brown, P. N., Hill, C. P. & Blair, D. F. Crystal structure of the middle and C-terminal domains of the flagellar rotor protein FliG. EMBO J. 21, 3225–3234 (2002)

    Article  CAS  Google Scholar 

  15. Francis, N. R., Irikura, V. M., Yamaguchi, S., DeRosier, D. J. & Macnab, R. M. Localization of the Salmonella typhimurium flagellar switch protein FliG to the cytoplasmic M-ring face of the basal body. Proc. Natl Acad. Sci. USA 89, 6304–6308 (1992)

    Article  ADS  CAS  Google Scholar 

  16. Ueno, T., Oosawa, K. & Aizawa, S. M ring, S ring and proximal rod of the flagellar basal body of Salmonella typhimurium are composed of subunits of a single protein, FliF. J. Mol. Biol. 227, 672–677 (1992)

    Article  CAS  Google Scholar 

  17. Kihara, M., Miller, G. U. & Macnab, R. M. Deletion analysis of the flagellar switch protein FliG of Salmonella. J. Bacteriol. 182, 3022–3028 (2000)

    Article  CAS  Google Scholar 

  18. Togashi, F., Yamaguchi, S., Kihara, M., Aizawa, S. I. & Macnab, R. M. An extreme clockwise switch bias mutation in fliG of Salmonella typhimurium and its suppression by slow-motile mutations in motA and motB. J. Bacteriol. 179, 2994–3003 (1997)

    Article  CAS  Google Scholar 

  19. Van Way, S. M., Millas, S. G., Lee, A. H. & Manson, M. D. Rusty, jammed, and well-oiled hinges: mutations affecting the interdomain region of FliG, a rotor element of the Escherichia coli flagellar motor. J. Bacteriol. 186, 3173–3181 (2004)

    Article  CAS  Google Scholar 

  20. Andrade, M. A., Petosa, C., O'Donoghue, S. I., Muller, C. W. & Bork, P. Comparison of ARM and HEAT protein repeats. J. Mol. Biol. 309, 1–18 (2001)

    Article  CAS  Google Scholar 

  21. Conti, E., Uy, M., Leighton, L., Blobel, G. & Kuriyan, J. Crystallographic analysis of the recognition of a nuclear localization signal by the nuclear import factor karyopherin α. Cell 94, 193–204 (1998)

    Article  CAS  Google Scholar 

  22. Huber, A. H., Nelson, W. J. & Weis, W. I. Three-dimensional structure of the armadillo repeat region of β-catenin. Cell 90, 871–882 (1997)

    Article  CAS  Google Scholar 

  23. Brown, P. N., Terrazas, M., Paul, K. & Blair, D. F. Mutational analysis of the flagellar protein FliG: sites of interaction with FliM and implications for organization of the switch complex. J. Bacteriol. 189, 305–312 (2007)

    Article  CAS  Google Scholar 

  24. Marykwas, D. L. & Berg, H. C. A mutational analysis of the interaction between FliG and FliM, two components of the flagellar motor of Escherichia coli. J. Bacteriol. 178, 1289–1294 (1996)

    Article  CAS  Google Scholar 

  25. Thomas, D. R., Francis, N. R., Xu, C. & DeRosier, D. J. The three-dimensional structure of the flagellar rotor from a clockwise-locked mutant of Salmonella enterica serovar Typhimurium. J. Bacteriol. 188, 7039–7048 (2006)

    Article  CAS  Google Scholar 

  26. Duke, T. A., Le Novere, N. & Bray, D. Conformational spread in a ring of proteins: a stochastic approach to allostery. J. Mol. Biol. 308, 541–553 (2001)

    Article  CAS  Google Scholar 

  27. Bai, F. et al. Conformational spread as a mechanism for cooperativity in the bacterial flagellar switch. Science 327, 685–689 (2010)

    Article  ADS  CAS  Google Scholar 

  28. Thomas, D., Morgan, D. G. & DeRosier, D. J. Structures of bacterial flagellar motors from two FliF–FliG gene fusion mutants. J. Bacteriol. 183, 6404–6412 (2001)

    Article  CAS  Google Scholar 

  29. Liu, J. 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. 191, 5026–5036 (2009)

    Article  CAS  Google Scholar 

  30. Murphy, G. E., Leadbetter, J. R. & Jensen, G. J. In situ structure of the complete Treponema primitia flagellar motor. Nature 442, 1062–1064 (2006)

    Article  ADS  CAS  Google Scholar 

  31. Leslie, A. G. W. in Joint CCP4 and ESF-EACMB Newsletter on Protein Cystallography No. 26 (Daresbury Laboratory, 1992)

    Google Scholar 

  32. Collaborative Computational Project Number 4 The CCP4 suite: programs for protein crystallography. Acta Crystallogr. D 50, 760–763 (1994)

    Article  Google Scholar 

  33. Leahy, D. J., Hendrickson, W. A., Aukhil, I. & Erickson, H. P. Structure of a fibronectin type III domain from tenascin phased by MAD analysis of the selenomethionyl protein. Science 258, 987–991 (1992)

    Article  ADS  CAS  Google Scholar 

  34. Sheldrick, G. M. A short history of SHELX. Acta Crystallogr. A 64, 112–122 (2008)

    Article  ADS  CAS  Google Scholar 

  35. Fortelle, E. & Bricogne, G. Maximum-likelihood heavy-atom parameter refinement for the multiple isomorphous replacement and multiwavelength anomalous diffraction methods. Methods Enzymol. 276, 472–494 (1997)

    Article  Google Scholar 

  36. Emsley, P. & Cowtan, K. Coot: model-building tools for molecular graphics. Acta Crystallogr. D 60, 2126–2132 (2004)

    Article  Google Scholar 

  37. Adams, P. D. et al. PHENIX: building new software for automated crystallographic structure determination. Acta Crystallogr. D 58, 1948–1954 (2002)

    Article  Google Scholar 

  38. Davis, I. W. et al. MolProbity: all-atom contacts and structure validation for proteins and nucleic acids. Nucleic Acids Res. 35, W375–W383 (2007)

    Article  ADS  Google Scholar 

  39. Dolinsky, T. J. et al. PDB2PQR: expanding and upgrading automated preparation of biomolecular structures for molecular simulations. Nucleic Acids Res. 35, W522–W525 (2007)

    Article  Google Scholar 

  40. Humphrey, W., Dalke, A. & Schulten, K. VMD: visual molecular dynamics. J. Mol. Graph. 14, 33–38 (1996)

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We thank the staff at beamline ID14-1 at the ESRF, and at beamlines 14-ID (BioCARS) and 23-ID (General Medicine and Cancer Institutes Collaborative Access Team (GM/CA-CAT)) at the APS for their support. Use of the APS was supported by the US Department of Energy, Basic Energy Sciences, Office of Science (contract DE-AC02-06CH11357), and use of the BioCARS Sector 14 was supported by the National Institutes of Health, National Center for Research Resources (grant RR007707). GM/CA-CAT was funded in whole or in part with federal funds from the National Cancer Institute (Y1-CO-1020) and the National Institute of General Medical Science (Y1-GM-1104). This work was supported by the Australian Synchrotron Research Program of the Australian Nuclear Science Technology Organization. D. Thomas is acknowledged for providing us with the electron microscopy density map of the clockwise-locked S. typhimurium mutant and O. Perisic and H. Huber are acknowledged for cloning vectors (pOPT-GST) and A. aeolicus genomic DNA, respectively. D.S. was initially funded by an MRC Career development award (UK) and C.C. by an MRC predoctoral fellowship (UK).

Author information

Authors and Affiliations

  1. Structural and Computational Biology Division, The Victor Chang Cardiac Research Institute, Lowy Packer Building, 405 Liverpool Street, Darlinghurst, New South Wales 2010, Australia,

    Lawrence K. Lee, Michael A. Ginsburg, Mhairi Donohoe & Daniela Stock

  2. MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK,

    Claudia Crovace

  3. Faculty of Medicine, University of New South Wales, Sydney, 2052, Australia

    Daniela Stock

Authors
  1. Lawrence K. Lee
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Michael A. Ginsburg
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Claudia Crovace
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Mhairi Donohoe
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Daniela Stock
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

L.K.L. collected synchrotron data, solved and analysed the structure, wrote software to generate FliG rings and switch morphs, and wrote the manuscript, M.D. collected synchrotron data, M.D. and M.A.G. purified and crystallized selenomethionine-containing protein, C.C. cloned, purified and crystallized the native protein, D.S. conceived and coordinated project, collected synchrotron data and wrote the manuscript.

Corresponding author

Correspondence to Daniela Stock.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

This file contains Supplementary Tables 1-2, Supplementary Figures 1-11 with legends, full legends for Supplementary Movies 1-6 and References. (PDF 3066 kb)

Supplementary Movie 1

This animated movie shows the formation of the FliG ring. (MOV 30576 kb)

Supplementary Movie 2

This movie shows the Interpolation of the M236 phi and F237 phi angles between the C-terminal conformations of FliGFL (CterFL) and FliGMC (CterMC). (MOV 908 kb)

Supplementary Movie 3

This movie shows a rotating FliG monomer displaying the equivalent residues at the location of all known rotationally biased mutants. (MOV 1526 kb)

Supplementary Movie 4

This movie shows parallels between the ARMC – ARMM+1 right-handed superhelix in the FliG multimer and a eukaryotic ARM superhelix in β-catenin. (MOV 3948 kb)

Supplementary Movie 5

This movie shows the structure of the FliGUNIT. (MOV 978 kb)

Supplementary Movie 6

This movie shows the reversal of the torque generating charges in the FliG ring. (MOV 1952 kb)

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Cite this article

Lee, L., Ginsburg, M., Crovace, C. et al. Structure of the torque ring of the flagellar motor and the molecular basis for rotational switching. Nature 466, 996–1000 (2010). https://doi.org/10.1038/nature09300

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature09300

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing