Crystallization and preliminary X-ray diffraction studies of arginase from a thermophilic organism Bacillus caldevelox

A thermostable hexameric arginase purified from the extreme thermophile Bacillus caldevelox has been crystallized from Hepes buffer at pH 7.5 in the presence of 12% polyethylene glycol 4000 and 10% 2-propanol, and from cacodylate buffer at pH 7.2 in the presence of 15% 2-propanol and sodium citrate. The latter crystals are more suitable for X-ray diffraction analysis. The crystals are in the orthorhombic space group P2₁2₁2₁ with unit-cell dimensions a = 156.3, b = 148.0 and c = 85.4 Å. The asymmetric unit contains one hexamer (approximate molecular mass 183 kDa) and has a solvent content of approximately 54%. The crystals diffract to 2.8 Å resolution.