ATP-driven rotation of the γ subunit in F₁-ATPase

We present a mechanism for F₁-ATPase in which hydrolysis of MgATP in the high-affinity catalytic site at the α/β interface drives rotation of the γ subunit via conformational changes in the α subunit. During hydrolysis, transition state formation and separation of P(i) from MgADP causes movement of portions of α, transmitted via two Arg residues which are hydrogen-bonded to the γ-phosphate of MgATP, αArg376 and βArg182; the latter is also hydrogen-bonded to interfacial α residues between α346 and α349. Changes in α conformation then push on γ, resulting in rotation. Supporting evidence from the literature and from new data is discussed. Copyright (C) 2000 Federation of European Biochemical Societies.