Large single crystals of spinach 1,5-bisphosphate carboxylase/oxygenase suitable for X-ray studies.

Large single crystals of a quaternary complex of spinach ribulose bisphosphate carboxylase, Mg2+, CO2 and the transition state analogue 2-C-carboxy-D-arabinitol-1,5-bisphosphate have been obtained from ammonium sulfate solutions. These crystals belong to space group C222 with cell dimensions a = 157.2 A, b = 157.2 A and c = 201.3 A. The crystals are pseudo F-centered with a pseudo 4-fold axis parallel to c. The space group of local symmetry F422 contains one large and one small subunit in the asymmetric unit. The crystals diffract beyond 2 A resolution.