Crystallization and preliminary high-resolution X-ray diffraction analysis of native and beta-mercaptoethanol-inhibited urease from Bacillus pasteurii

Hexagonal crystals of urease from Bacillus pasteurii have been obtained by vapour diffusion at 293 K in 20 mM Tris-HCl, neutral pH, containing 50 mM Na2SO3. Isomorphous crystals of urease inhibited with beta-mercaptoethanol were also obtained by including 4 mM of the inhibitor in the enzyme solution. Crystals of the native and inhibited enzyme diffract, respectively, to 2.00 Angstrom (96.7% completeness) and to 1.65 Angstrom (98.7% completeness) using synchrotron X-ray cryogenic (100 K) conditions. The space group is P6(3)22 for both forms, and the unit-cell parameters are a = b = 131.36, c = 189.76 Angstrom for native urease and a = b = 131.34, c = 190.01 Angstrom for inhibited urease. Under the same conditions, single crystals of B. pasteurii urease inhibited with acetohydroxamic acid, cisteamine and phenylphosphorodiamidate were also obtained.