| X-RAY DIFFRACTION |
7.0 |
281.15 |
1-ml mixture containing 120 mM potassium phosphate pH 6.0, 1 mM EDTA, 26 uM (1 mg/ml) [Fe]-hydrogenase and 26 uM methylene-H4MPT was incubated in 5-ml amber vials with rubber stoppers under a gas mixture of N2/O2/H2 (70%/20%/10%) at 40 degree Celsius for 1 h. The inactivated enzyme was concentrated to 25 mg/ml using a 30 kDa centrifugal filter (Millipore). 0.7-ul of 25 mg/ml O2-inactivated [Fe]-hydrogenase was mixed with 0.7 ul of reservoir solution of 2 M (NH4)2SO4, 100 mM Tris/HCl, pH 7.0, and 200 mM LiSO4. The best diffracting crystal was obtained in one month. Prior to freezing the crystal was soaked for 3 seconds in 2 M (NH4)2SO4, 100 mM Tris/HCl, pH 7.0, 200 mM LiSO4 and 30% glycerol v/v. |
