Expression, purification and preliminary crystallographic analysis of phosphoribosyl isomerase (PriA) from Streptomyces coelicolor

The priA gene encoding the enzyme phosphoribosyl isomerase from Streptomyces coelicolor, a novel bifunctional enzyme involved in both histidine and tryptophan biosynthesis, was heterologously expressed and purified in Escherichia coli as an N-terminal His-tag fusion. The purified recombinant enzyme was crystallized using the hanging-drop method in 1.50 M ammonium sulfate and 100 mM sodium citrate pH 4.8. Crystals were obtained of up to 0.05 × 0.05 × 0.3 mm in size. A full data set to 2 Å resolution was collected at the ESRF beamline ID14-1 and space group P3_1,221 was assigned, with unit-cell parameters a = 65.1, c = 104.7 Å.