5.1.2.1 | purified enzyme, free or Hg-labeled, hanging drop vapour diffusion method, mixing of 0.002 ml of 16 mg/ml protein solution with 0.002 ml of reservoir solution containing 22% PEG monomethyl ether 5000, 0.2 M ammonium sulfate, 0.1 M MES pH 6.5, 0.2 M sodium malonate pH 7.0 and 0.02% w/v sodium azide, at 18°C, a few days, X-ray diffraction structure determination and analysis at 1.8-2.0 A resolution |