Essential Role of the ε Subunit for Reversible Chemo-Mechanical Coupling in F₁-ATPase.

ABSTRACT: F₁-ATPase is a rotary motor protein driven by ATP hydrolysis. Among molecular motors, F₁ exhibits unique high reversibility in chemo-mechanical coupling, synthesizing ATP from ADP and inorganic phosphate upon forcible rotor reversal. The ε subunit enhances ATP synthesis coupling efficiency to > 70% upon rotation reversal. However, the detailed mechanism has remained elusive. In this study, we performed stall-and-release experiments to elucidate how the ε subunit modulates ATP association/dissociation and hydrolysis/synthesis process kinetics and thermodynamics, key reaction steps for efficient ATP synthesis. The ε subunit significantly accelerated the rates of ATP dissociation and synthesis by two- to fivefold, whereas those of ATP binding and hydrolysis were not enha

SUBMITTER: Watanabe R 

PROVIDER: S-EPMC5773760 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature