Protein preparation, crystallization and preliminary X-ray crystallographic studies of a thermostable hypoxanthine–guanine phosphoribosyltransferase from Thermoanaerobacter tengcongensis

Native and His-tagged mutant (L160I) hypoxanthine–guanine phosphoribosyltransferase (HGPRT) from Thermoanaerobacter tengcongensis were cloned, expressed in Escherichia coli and purified. Both proteins were crystallized with polyethylene glycol as the main precipitant at 293 K using the hanging-drop vapour-diffusion method. The crystal of native HGPRT belongs to space group C222₁, with unit-cell parameters a = 65.77, b = 137.73, c = 95.27 Å, and diffracted to 2.2 Å resolution on an in-house X-ray generator. The crystal of the His-tagged mutant (L160I) HGPRT belongs to the space group I222, with unit-cell parameters a = 52.21, b = 88.36, c = 93.03 Å, and diffracted to 1.7 Å resolution in-house.