FIG. 1.

Diagram of the C. crescentus flagellum. The flagellar structure is adapted from references 12 and 22. Flagellar components encoded by class II genes are light gray, components encoded by class III genes are dark gray, and the filament (class IV) is black. Class I is assigned to genes that are required for the activation of class II genes. The flagellar substructures are indicated on the right. Approximately 26 FliF protein subunits form the MS ring structure in the inner membrane (light gray with hatching). Rotation is conferred by proton flow through stator protein MotA of the force-generating unit in interaction with the rotor C ring protein FliG (22). Abbreviations: IM, inner membrane; CW, cell wall (peptidoglycan layer); OM, outer membrane.