FIGURE 8.

Movements associated with switching to clockwise rotation. A, effects of repellent stimuli on cross-link yields. The experiments used iodine to induce cross-linking in intact cells. Upper panels, effects of leucine (30 mm). Lower panels, effects of glycerol (10%). B, Cys pairs that showed altered cross-link yields upon treatment with repellent mapped onto the FliN₄-FliM_C-FliN₄ structural model. The affected cross-links are on the left-hand interface, and the changes in cross-link yield can be accounted for by a displacement along the interface in the direction indicated. The magnitude of the displacement cannot yet be estimated precisely; inter-sulfur distances that would result from a 7-Ådisplacement are indicated. C, comparison of the FliM_C-FliN structural model (upper panel, five FliN tetramers and four FliM_C domains are shown in the arrangement corresponding to the clockwise state) with an image of the bottom of the basal body from EM reconstructions on a clockwise-locked mutant (4).