4.2.1.109 | purified recombinant His-tagged enzyme fragment of residues 20-242, hanging drop vapour diffusion method, 0.001 ml of protein solution, containing 20 mM Tris-HCl, 5% v/v glycerol, 0.1 mM TCEP, 100 mM sodium chloride, pH 8.0, is mixed with 0.001 ml of reservoir solution, containing 0.04 M citric acid, 0.06 M Bis-Tris propane, 5% v/v glycerol, 18-21% w/v PEG 3350, and equilibrated against 0.2 ml of reservoir solution, 22°C, 5 days to 2 weeks, X-ray diffraction structure determination and analysis at 2.40 A resolution |