FIG  7 .

Model showing the location and function of FliL at the motor. FliL is positioned to interact closely with both the stators and the MS ring (side view of the flagellum and cross view of the MS ring and stators). This arrangement stabilizes the stators and enhances proton flow/efficiency, delivering a higher torque, as depicted on the left side of the flagellum image. Interaction of FliL with FliG as well as MotA (which interacts with FliG) contributes to the switching behavior of the motor. The lower rotation speed in the absence of FliL is depicted on the right side of the flagellum image. Strong FliL-FliL interactions suggest that FliL is at least a dimer, as indicated in the cross view. Association of FliL with the MS ring protein FliF may reinforce the rod, helping it to withstand high external load during swarming. IM, inner membrane; PG, peptidoglycan layer; OM, outer membrane.