5.3.2.6 4-OT from 80% saturated ammonium sulfate solution containing 100 mM HEPES, pH 7.5, and 1% PEG 200, 20°C, X-ray diffraction structure determination and analysis at 1.9-2.8 A resolution, heavy etal derivatization by soaking the crystals for 4 h in crystallization solution containing 2 mM K2PtCl4 718825 5.3.2.6 crystals are grown from 20% dioxane and 50% 2-methyl-2,4-pentanediol, pH 6.0, vapor diffusion method 721792 5.3.2.6 crystals are grown from 28% polyethylene glycol 400, 200 mM CaCl2, 0.1 M HEPES buffer (pH 7.5), vapor diffusion method 721792 5.3.2.6 hanging drop vapor diffusion method, using 200 mM tri-ammonium citrate and 10% (w/v)polyethylene glycol (PEG) 3350 726816 5.3.2.6 mutant enzyme M45Y/F50A, sitting drop vapor diffusion method, using 0.2 M sodium formate, 0.1 M bis-tris propane pH 8.5 and 20% PEG 3350 (w/v) 748742 5.3.2.6 purified recombinant hh4-OT, by sitting drop vapour diffusion method, 0.001 ml of 20 mg/mL protein in 10 mM Na/KPO4 buffer, pH 7.3, is mixed in a 1:1 ratio with precipitant against a 0.1 ml reservoir solution, and by hanging drop vapor diffusion method with a 0.5 ml reservoir and 0.004 ml hanging drops that contain protein and precipitant, 0.25 M (NH4)2SO4 and 4% PEG 4000, in a 1:1 ratio, 3-5 days, X-ray diffraction structure determination and analysis at 2.41 A resolution 718874 5.3.2.6 sitting drop vapor diffusion method, using 100 mM magnesium acetate/100 mM sodium acetate, 5%-21% (w/v) PEG 8000, pH 4.5, and 100 mM calcium acetate/100 mM sodium acetate, 1%-13% (w/v) PEG 4000, pH 4.5 726964