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bioRxiv · 10.1101/2022.12.23.521728

Mechanism of ATP hydrolysis dependent rotation of ATP synthases

Nakano, A.·Kishikawa, J.-i.·Mitsuoka, K.·Yokoyama, K.
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Abstract

F1 domain of ATP synthase is a rotary ATPase complex in which rotation of central {gamma}-subunit proceeds in 120{degrees} steps against a surrounding 3{beta}3 fueled by ATP hydrolysis. How the ATP hydrolysis reactions occurring in three catalytic {beta} 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{degrees} rotation occur simultaneously in F1 domain when nucleotides are bound at all the three catalytic {beta} dimers. The remaining 40{degrees} rotation of the complete 120{degrees} step is driven by completion of ATP hydrolysis at D{beta}D, and proceeds through three sub-steps (83{degrees}, 91{degrees}, 101{degrees}, and 120{degrees}) with three associated conformational intermediates. All sub-steps except for one between 91{degrees} and 101{degrees} associated with phosphate release, occur independently of the chemical cycle, suggesting that the 40{degrees} rotation is largely driven by release of intramolecular strain accumulated by the 80{degrees} rotation. Together with our previous results, these findings provide the molecular basis of ATP driven rotation of ATP synthases.

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Nakano, A., Kishikawa, J.-i., Mitsuoka, K., Yokoyama, K.. 2022-12-23. Mechanism of ATP hydrolysis dependent rotation of ATP synthases. https://doi.org/10.1101/2022.12.23.521728

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