6.1.1.16 | purified recombinant free enzyme or cysteine and ATP complexed enzyme, hanging-drop vapour diffusion method, 17°C, 0.001 ml protein solution: 6 mg/ml enzyme, 10 mM HEPES, pH 7.4, 50 mM NaCl, 1 mM DTT, 5 mM MgCl2, 5 mM ATP, 10 mM cysteine, plus equal volume of reservoir solution: 0.1 M sodium cacodylate, pH 6.5, 15-17% PEG 8000, 0.2 M magnesium acetate, 2% tert-butanol, 1-3 weeks, cysteine but not ATP is required for crystal growth, X-ray diffraction structure determination at 2.3-3.0 A resolution, and analysis |