The structural and functional connection between the catalytic and proton translocating sectors of the mitochondrial F1F0-ATP synthase

The structural and functional connection between the peripheral catalytic F -1 sector and the proton-translocating membrane sector F-o of the mitochond rial ATP synthase is reviewed. The observations examined show that the N-te rminus of subunit gamma, the carboxy-terminal and central region of FoI-PVP (b), OSCP, and part of subunit d constitute a continuous structure, the lat eral stalk, which connects the peripheries of F-1 to F-o and surrounds the central element of the stalk, constituted by subunits gamma and delta. The ATPase inhibitor protein (IF1) binds at one side of the F1Fo connection. Th e carboxy-terminal segment of IF1 apparently binds to OSCP. The 42L-58K seg ment of IF1 which is per se the most active domain of the protein, binds at the surface of one of the three alpha/beta pairs of F-1, thus preventing t he cyclic interconversion of the catalytic sites required for ATP hydrolysi s.