FIG 1.

Flagellar motor structure. Stator complexes assemble in a ring in the inner membrane. Each stator unit is formed by four MotA and two MotB proteins, and the MotB protein anchors the complex to peptidoglycan. Each stator unit forms two channels through which ions can flow (H⁺ indicates protons in this example, with arrow indicating the direction of ion flow). Electrostatic interactions between the MotA and FliG proteins in the C ring generate the torque necessary to power rotation of the flagellum. OM, outer membrane; PG, peptidoglycan; IM, inner membrane. The arrow at the base of the motor indicates a motor complex capable of rotating the flagellum. Copyright, William Scavone; used with permission.