Fig. 5.

Model of stator assembly in the sodium ion-driven polar flagellar motor of Vibrio. MotY is shown as a space-filling model colored blue for MotY-N and yellow for MotY-C. MotX, PomA, and PomB are shown in orange, dark green, and light green, respectively. (A) MotX and MotY form a complex and diffuse around in the periplasm without binding to the peptidoglycan layer. (B) Interaction of the MotX/MotY complex with the flagellar basal body triggers a conformational change in MotY-C that increases its affinity for the peptidoglycan layer, and the complex associates tightly with the basal body via MotY-N to form the T-ring. The PomA/PomB stator complex diffuses through the membrane. (C) The PomA/PomB complexes assemble around the rotor through association with MotX in the T-ring and binding to the peptidoglycan layer via the C-terminal domain of PomB.