Large conformational changes of the epsilon subunit in the bacterial F1F0 ATP synthase provide a ratchet action to regulate this rotary motor enzyme.

ABSTRACT: The F(1)F(0) ATP synthase is the smallest motor enzyme known. Previous studies had established that the central stalk, made of the gamma and epsilon subunits in the F(1) part and c subunit ring in the F(0) part, rotates relative to a stator composed of alpha(3)beta(3)deltaab(2) during ATP hydrolysis and synthesis. How this rotation is regulated has been less clear. Here, we show that the epsilon subunit plays a key role by acting as a switch of this motor. Two different arrangements of the epsilon subunit have been visualized recently. The first has been observed in beef heart mitochondrial F(1)-ATPase where the C-terminal portion is arranged as a two-alpha-helix hairpin structure that extends away from the alpha(3)beta(3) region, and toward the position of the c subunit ring in the intact

SUBMITTER: Tsunoda SP 

PROVIDER: S-EPMC34392 | biostudies-literature | 2001 Jun

REPOSITORIES: biostudies-literature