ATP synthase from Escherichia coli: Mechanism of rotational catalysis, and inhibition with the ε subunit and phytopolyphenols

Abstract ATP synthases (F o F 1 ) are found ubiquitously in energy-transducing membranes of bacteria, mitochondria, and chloroplasts. These enzymes couple proton transport and ATP synthesis or hydrolysis through subunit rotation, which has been studied mainly by observing single molecules. In this review, we discuss the mechanism of rotational catalysis of ATP synthases, mainly that from Escherichia coli , emphasizing the high-speed and stochastic rotation including variable rates and an inhibited state. Single molecule studies combined with structural information of the bovine mitochondrial enzyme and mutational analysis have been informative as to an understanding of the catalytic site and the interaction between rotor and stator subunits. We discuss the similarity and difference in structure and inhibitory regulation of F 1 from bovine and E. coli . Unlike the crystal structure of bovine F 1 (α 3 β 3 γ), that of E. coli contains a e subunit, which is a known inhibitor of bacterial and chloroplast F 1 ATPases. The carboxyl terminal domain of E. coli e (eCTD) interacts with the catalytic and rotor subunits (β and γ, respectively), and then inhibits rotation. The effects of phytopolyphenols on F 1 -ATPase are also discussed: one of them, piceatannol, lowered the rotational speed by affecting rotor/stator interactions.