Myosin cleft closure determines the energetics of the actomyosin interaction.

ABSTRACT: Formation of the strong binding interaction between actin and myosin is essential for force generation in muscle and in cytoskeletal motor systems. To clarify the role of the closure of myosin's actin-binding cleft in the actomyosin interaction, we performed rapid kinetic, spectroscopic, and calorimetric experiments and atomic-level energetic calculations on a variety of myosin isoforms for which atomic structures are available. Surprisingly, we found that the endothermic actin-binding profile of vertebrate skeletal muscle myosin subfragment-1 is unique among studied myosins. We show that the diverse propensity of myosins for cleft closure determines different energetic profiles as well as structural and kinetic pathways of actin binding. Depending on the type of myosin, strong actin bindi

SUBMITTER: Takacs B 

PROVIDER: S-EPMC3005428 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature