Allosteric Communication in Myosin V: From Small Conformational Changes to Large Directed Movements
Figure 1
The Lymn–Taylor functional cycle of the actomyosin complex [6],[13] (adapted from Yu et al. [19] to indicate the motion of the lever arm appropriate for myosin V).
Only a myosin monomer is shown for simplicity. Binding of ATP to the actomyosin complex (the rigor state) leads to rapid dissociation of myosin from actin without immediate hydrolysis of ATP. Coupled with a major structural change in the orientation of the lever arm (“recovery stroke”), ATP hydrolysis proceeds and the motor domain weakly rebinds to actin. Following the release of Pi, the motor domain undergoes the “powerstroke” during which the lever arm moves back to the rigor state and the motor domain becomes strongly bound to actin. Dissociation of ADP leads the system back to the rigor state.