Mechanism of ATP hydrolysis dependent rotation of ATP synthases

Abstract

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.

Rotary mechanism of V/A-ATPases—how is ATP hydrolysis converted into a mechanical step rotation in rotary ATPases?

“…This makes the rotational mechanism of the F 1 -ATPase more complex than that of the V/A-ATPase, but the underlying principle remains the same. Our recent structural snapshot analysis of F o F 1 supports this, suggesting that F o F 1 converts the downhill chemical potential generated by ATP hydrolysis into a mechanical step through a similar mechanism ( Nakano et al, 2022 ). This highlights the importance of both ATP binding and hydrolysis in the generation of rotational forces by rotary ATPases.…”

Dimeric assembly of F1-like ATPase for the gliding motility ofMycoplasma

“…3a). We named these conformations Gliβ C (closed), Gliβ HO (half-open), and Gliβ O (open), following the conformation names of F 1 -ATPase 8 . They are arranged clockwise when viewed from the C-terminus of the hexameric ring (Fig.…”

“…This study aimed to elucidate the detailed structure of the twin motor using cryo-EM single-particle analysis (SPA). Notably, the structural features had a strong homology to those of F1-ATPase 7,8 , suggesting a rotary catalytic mechanism analogous to that of rotary ATPase 1,9,10 for the gliding motility of M. mobile.…”