The structure of full-length FliG from Aquifex aeolicus

Experimental Data Snapshot

  • Resolution: 2.40 Å
  • R-Value Free: 0.270 
  • R-Value Work: 0.216 
  • R-Value Observed: 0.219 

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

Lee, L.K.Ginsburg, M.A.Crovace, C.Donohoe, M.Stock, D.

(2010) Nature 466: 996-1000

  • DOI: https://doi.org/10.1038/nature09300
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The flagellar motor drives the rotation of flagellar filaments at hundreds of revolutions per second, efficiently propelling bacteria through viscous media. The motor uses the potential energy from an electrochemical gradient of cations 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 trajectory. A protein called FliG forms a ring in the rotor of the flagellar motor that is involved in the generation of torque through an interaction with the cation-channel-forming stator subunit MotA. 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.

  • Organizational Affiliation

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

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Flagellar motor switch protein fliG329Aquifex aeolicusMutation(s): 0 
Find proteins for O66891 (Aquifex aeolicus (strain VF5))
Explore O66891 
Go to UniProtKB:  O66891
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO66891
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.40 Å
  • R-Value Free: 0.270 
  • R-Value Work: 0.216 
  • R-Value Observed: 0.219 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 59.997α = 90
b = 65.84β = 110.99
c = 67.791γ = 90
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
ADSCdata collection
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-08-04
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2024-03-20
    Changes: Data collection, Database references