Force-producing ADP state of myosin bound to actin

Significance
The force-generating state of myosin bound to actin is a key state in the chemomechanical cycle of this motor, but the structural details of the force-generating state are unknown. CryoEM structures of myosin V bound to actin with and without nucleotide reveal a previously unidentified conformation of elements associated with nucleotide binding and, most importantly, of the β-sheet that controls the position of nucleotide-binding elements. These specific structural features explain how myosin can bind strongly to both actin and MgADP, allowing force to be developed. Thus, this structure provides fundamental insights into how myosin works. It also provides insights into how strain may prevent release of MgADP, which is a critical property for the cellular roles of many myosins, including myosin V.