Quaternary structure of V1 and F1 ATPase: significance of structural homologies and diversities

The quaternary structure of the V1 ATPase from the tobacco hornworm Manduca sexta and the F1 ATPase from Escherichia coli was characterized using small-angle X-ray scattering. The radii of gyration of the V1 and F1 complexes as well as the shape of the V1 ATPase were also determined. Experimental results showed that a seventh mass, which is thought to be the stalk that links V1 with the membrane domain V0 in the intact V1V0-ATPase, extends perpendicularly to the center of the hexameric unit.