Nature 402, 263-268 (1999)

Structural changes linked to proton translocation by subunit c of the ATP synthase

Vinit K. Rastogi and Mark E. Girvin

F₁F_O ATP synthases use a transmembrane proton gradient to drive the synthesis of cellular ATP. The structure of the cytosolic F₁ portion of the enzyme and the basic mechanism of ATP hydrolysis by F₁ are now well established, but how proton translocation through the transmembrane F_O portion drives these catalytic changes is less clear. Here we describe the structural changes in the proton-translocating F_O subunit c that are induced by deprotonating the specific aspartic acid involved in proton transport. Conformational changes between the protonated and deprotonated forms of subunit c provide the structural basis for an explicit mechanism to explain coupling of proton translocation by F_O to the rotation of subunits within the core of F₁. Rotation of these subunits within F₁ causes the catalytic conformational changes in the active sites of F₁ that result in ATP synthesis.