Crystallization and preliminary X-ray diffraction analysis of orotate phosphoribosyltransferase from the human malaria parasite Plasmodium falciparum

Orotate phosphoribosyltransferase (OPRT) catalyzes the Mg²⁺-dependent condensation of orotic acid (OA) with 5-α-D-phosphorylribose 1-diphosphate (PRPP) to yield diphosphate (PP_i) and the nucleotide orotidine 5′-monophos­phate. OPRT from Plasmodium falciparum produced in Escherichia coli was crystallized by the sitting-drop vapour-diffusion method in complex with OA and PRPP in the presence of Mg²⁺. The crystal exhibited tetragonal symmetry, belonging to space group P4₁ or P4₃, with unit-cell parameters a = b = 49.15, c = 226.94 Å. X-ray diffraction data were collected to 2.5 Å resolution at 100 K using a synchrotron-radiation source.