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

摘要

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 Å (96.7% completeness) and to 1.65 Å (98.7% completeness) using synchrotron X-ray cryogenic (100 K) conditions. The space group is P6322 for both forms, and the unit-cell parameters are a = b = 131.36, c = 189.76 Å for native urease and a = b = 131.34, c = 190.01 Å for inhibited urease. Under the same conditions, single crystals of B. pasteurii urease inhibited with acetohydroxamic acid, cisteamine, and phenylphosphorodiamidate were also obtained.