Mechanical rotation of the c subunit oligomer in ATP synthase (F0F1): Direct observation

F0F1, found in mitochondria or bacterial membranes, synthesizes adenosine 5 '-triphosphate (ATP) coupling with an electrochemical proton gradient and a lso reversibly hydrolyzes ATP to form the gradient. An actin filament conne cted to a c subunit oligomer of F-0 was able to rotate by using the energy of ATP hydrolysis. The rotary torque produced by the c subunit oligomer rea ched about 40 piconewton-nanometers, which is similar to that generated by the gamma subunit in the F-1 motor. These results suggest that the gamma an d c subunits rotate together during ATP hydrolysis and synthesis. Thus, cou pled rotation may be essential for energy coupling between proton transport through F-0 and ATP hydrolysis or synthesis in F-1.