Crystallization and preliminary X-ray diffraction studies on the Apo form of orotate phosphoribosyltransferase from Escherichia coli.

Three different crystal forms of the apoenzyme orotate phosphoribosyltransferase, with M(r) = 23,552 from Escherichia coli have been grown. The crystals, which are all suitable for X-ray diffraction analysis, have been grown by the hanging drop vapour diffusion method. The first form crystallizes in the orthorhombic space group P2(1)2(1)2, with cell dimensions: a = 136.34 A, b = 75.98 A and c = 40.32 A; the second form in the monoclinic space group P2, with unit cell dimensions: a = 101.61 A, b = 40.49 A, c = 79.05 A and beta = 87.33 degrees; and the third form in P2(1)2(1)2(1), the cell dimensions being a = 70.27 A, b = 103.53 A, c = 53.83 A.