4.4.1.9	purified recombinant wild-type and K95A mutant enzymes, hanging drops vapor diffusion method , 0004 ml of 10-12 mg/ml protein solution is mixed with an equal volume of crystallization solution containing 10% PEG 8000, 0.2 M NaCl, and 0.1 sodium/potassium phosphate, pH 7.0, and 0.2 M MgSO4, at 4°C over a 0.7 mL reservoir. The K95A mutant is crystallized in similar drops from a solution containing 20% PEG 3350, 0.2 M potassium citrate, pH 7.5, X-ray diffraction structure determination and analysis at 2.50 A and 1.77 A resolution, respectively, molecular replacement	730601