Fig. 5.

Off-axis strain accelerates ADP release. Cartoon representation of MV-4IQ-HMM attached to a segment of actin. The lead head is shown bound at the second, sixth, seventh, and 11th actin subunit, corresponding to a span of 5.5, 16.5, 19.3, and 30.3 nm between the two heads. The intermediate distances require the myosin to twist around the actin helix, as shown by the arrows indicating the orientation of each myosin head. Processive steps from MV-4IQ-HMM at 10 μM ATP were collected into 4-nm bins, and the times for the preceding and following dwells were fit to two rates. Closed symbols show the two rates that best-fit prestep dwells, and open symbols show the rates derived from poststep dwells.