Rotational symmetry of the C ring and a mechanism for the flagellar rotary motor.
FliG, FliM, and FliN, key proteins for torque generation, are located in two rings. The first protein is in the M ring and the last two are in the C ring. The rotational symmetries of the C and M rings have been determined to be about 34 (this paper) and 26 (previous work), respectively. The mechanism proposed here depends on the symmetry mismatch between the rings: the C ring extends 34 levers, of which 26 can bind to the 26 equivalent sites on the M ring. The remaining 8 levers bind to proton-pore complexes (studs) to form 8 torque generators. Movement results from the swapping of stud-bound levers with M ring-bound levers. The model predicts that both the M and C rings rotate in the same direction but at different speeds.
Thomas
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W. M. Keck Institute for Cellular Visualization, Rosenstiel Basic Medical Sciences Research Center, Department of Biology, Brandeis University, Waltham, MA 02254, USA.
Morgan
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DeRosier
D J
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D001426:Bacterial Proteins / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure*; D005407:Flagella / Q000502:physiology / Q000648:ultrastructure; D008854:Microscopy, Electron; D008958:Models, Molecular; D008961:Models, Structural; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000648:ultrastructure; D012399:Rotation; D019415:Torque
D001426:Bacterial Proteins; C077389:FliN protein, Bacteria; C075660:Flig protein, Bacteria; D011993:Recombinant Fusion Proteins; C066821:FliM protein, Bacteria