Adenosine triphosphatase from rat liver mitochondria. Crystallization and x-ray diffraction studies of the F1-component of the enzyme.

The homogeneous rat liver F1-ATPase preparation of Catterall and Pedersen (Catterall, W.A., and Pedersen, P.L. (1971) J. Biol. Chem. 246, 4987-4994) has been crystallized from a solution containing phosphate and ATP by precipitation with ammonium sulfate. Most of the resultant crystals are cubes of approximately 0.3 to 0.6 mm per side. X-ray precession photographs show that the crystals are rhombohedral, space group R32 (D37 NO155) with hexagonal cell dimensions a = 148 A, c = 368 A. The molecular weight of the asymmetric unit of the crystals is 190,000 or about half the molecular weight (384,000) of the rat liver enzyme indicating that the crystallographic 2-fold axes of symmetry coincide with a molecular symmetry axis. The crystals diffract to at least 3.5 A and therefore this is the first report of an ATPase preparation in which crystals suitable for x-ray analysis have been obtained.