Mechanism of ATP hydrolysis dependent rotation of ATP synthases

F1 domain of ATP synthase is a rotary ATPase complex in which rotation of central gamma-subunit proceeds in 120 degree steps against a surrounding alpha3beta3 fueled by ATP hydrolysis. How the ATP hydrolysis reactions occurring in three catalytic alphabeta dimers are coupled to mechanical rotation is a key outstanding question. Here we describe catalytic intermediates of the F1 domain during ATP mediated rotation captured using cryo-EM. The structures reveal that three catalytic events and the first 80 degree rotation occur simultaneously in F1 domain when nucleotides are bound at all the three catalytic alphabeta dimers. The remaining 40 degree rotation of the complete 120 degree step is driven by completion of ATP hydrolysis at alphaDbetaD, and proceeds through three sub-steps (83 degree, 91 degree, 101 degree, and 120 degree) with three associated conformational intermediates. All sub-steps except for one between 91 degree and 101 degree associated with phosphate release, occur independently of the chemical cycle, suggesting that the 40 degree rotation is largely driven by release of intramolecular strain accumulated by the 80 degree rotation. Together with our previous results, these findings provide the molecular basis of ATP driven rotation of ATP synthases. ### Competing Interest Statement The authors have declared no competing interest.