Cloning, expression and crystallization of pyrimidine nucleoside phosphorylase from Bacillus stearothermophilus

Pyrimidine nucleoside phosphorylase (PYNP) from B. stearothermophilus has been cloned and purified for crystallization. Crystals of a potential protein–inhibitor complex have been prepared by co-crystallization techniques using the substrate analog pseudouridine. These crystals provide good-quality diffraction images to 2.7 Å and belong to space group P2₁. The asymmetric unit contains the dimer structure of PYNP with unit-cell parameters a = 53.9, b = 71.9, c = 123.3 Å and β = 96.9°.