Recent progress in single-molecule detection techniques is remarkable. Thes
e techniques have allowed the accurate determination of myosin-head-induced
displacements and how mechanical cycles are coupled to ATP hydrolysis, by
measuring individual mechanical events and chemical events of actomyosin di
rectly at the single-molecule level. Here we review our recent work in whic
h we have made detailed measurements of myosin step size and mechanochemica
l coupling, and propose a model of the myosin motor.