Structural Comparison of F1-ATPase: Interplay among Enzyme Structures, Catalysis, and Rotations

SummaryF1-ATPase, a rotary motor powered by adenosine triphosphate hydrolysis, has been extensively studied by various methods. Here, we performed a systematic comparison of 29 X-ray crystal structures of F1-complexes, finding fine interplay among enzyme structures, catalysis, and rotations. First, analyzing the 87 structures of enzymatic αβ-subunits, we confirmed that the two modes, the hinge motion of β-subunit and the loose/tight motion of the αβ-interface, dominate the variations. The structural ensemble was nearly contiguous bridging three clusters, αβTP, αβDP, and αβE. Second, the catalytic site analysis suggested the correlation between the phosphate binding and the tightening of the αβ-interface. Third, addressing correlations of enzymatic structures with the orientations of the central stalk γ, we found that the γ rotation highly correlates with loosening of αβE-interface and βDP hinge motions. Finally, calculating the helix 6 angle of β, we identified the recently observed partially closed conformation being consistent with βHC.

► Structural comparison of 87 αβ enzyme structures and catalytic sites was performed ► Rotary and tilting angles of γ were calculated for 29 F1-complexes ► We found γ-rotation highly correlates with αβE-interface and βDP hinge structures ► From modeling of helix6, the partially closed conformation may correspond to βHC