Dynamic and coordinating domain motions in the active subunits of the F1-ATPase molecular motor

F1-ATPase is a rotary molecular motor crucial for various cellular functions. In F1-ATPase, the rotation of the γδε subunits against the hexameric α3β3 subunits is highly coordinative, driven by ATP hydrolysis and structural changes at three β subunits. However, the dynamical and coordinating structural transitions in the β subunits are not fully understood at the molecular level. Here we examine structural transitions and domain motions in the active subunits of F1-ATPase via dynamical domain analysis of the α3β3γδε complex. The domain movement and hinge axes and bending residues have been identified and determined for various conformational changes of the β-subunits. P-loop and the ATP-binding pocket are for the first time found to play essential mechanical functions additional to the catalytic roles. The cooperative conformational changes pertaining to the rotary mechanism of F1-ATPase appears to be more complex than Boyer's ‘bi-site’ activity. These findings provide unique molecular insights into dynamic and cooperative domain motions in F1-ATPase.