Dynamic Structure Change due to ATP Hydrolysis in the Motor Domain of Myosin: Molecular Dynamics Simulations

The muscle contraction is caused by directed movement of the myosin head along the actin filament. This movement is triggered by ATP hydrolysis, which occurs in the motor domain of myosin. The mechanism for its intra-molecular process remains unknown because of a lack of way to observe vibrational motions of each atom in a myosin molecule. We have carried out 10-ns, all-atom molecular dynamics (MD) simulations to examine what kinds of dynamic structure changes of the motor domain are produced by the energy released from an ATP hydrolysis. The result revealed that a disturbance due to the ATP hydrolysis enhances collective motions of atoms at the actin-binding site and the junction with the neck, both of which are relevant to the movement of the myosin head along the actin filament. Further, an ATP hydrolysis was found to open the gate to the ATIPase pocket for the following ATP molecule to easily get into there.