5.1.3.17 | purified enzyme in apo-form and in complex with heparin hexasaccharide, both in a stable dimer conformation, hanging drop vapour diffusion method, mixing of 0.001 ml of 15-20 mg/ml protein in in 20 mM Tris, pH 8.0, 200 mM ammonium acetate, 1 mM dithiothreitol, and 1 mM EDTA, with 0.001 ml of 16% w/v PEG 3350, 0.1 M sodium citrate tribasic dihydrate, pH 5.6, and 2% v/v Tacsimate, pH 5.0 for the unlabeled enzyme and 16% w/v PEG 3350, 0.06 M citric acid, and 0.04 M Bis-Tris propane, pH 4.1, for the SeMet-labeled enzyme, a concentration of 5.0 mg/ml is used for the enzyme complex with heparin oligosaccharide at a molar ratio of 1:5, 20°C, 3 days, X-ray diffraction structure determination and analysis at 1.9-2.2 A resolution |