The recombinant version of Trypanosoma cruzi pteridine reductase was expressed in Escherichia coli, purified to homogeneity from the soluble fraction of bacterial extract by metal-chelate affinity chromatography and crystallized in the presence of the cofactor (NADPH) and an inhibitor (methotrexate) at 295 K using sodium acetate as precipitant. The crystals are trigonal, belonging to space group P31 (or P32), with unit-cell parameters a = 74.35, c = 179.96 Å under cryogenic conditions. The asymmetric unit contains a tetramer, with a corresponding VM of 2.3 Å3 Da-1 and a solvent content of 46%. Native data have been collected to 2.1 Å resolution using Cu Kα X-rays.
