4.2.2.19 6-8 mg/ml purified recombinant enzyme, residues 25-506, in 20 mM Tris-HCl, pH 8.0, 1 mM sodium phosphate, pH 7.0, 3 mM NaCl, 0.5 mM phenylmethylsulfonyl fluoride, 0.001 mg/ml aprotinin, 0.001 mg/ml leupeptin, 0.001 mg/ml E64, hanging drop vapour diffusion method, 292 K, mixed with a double volume of reservoir solution containing 19% w/v PEG 8000, 100 mM bicine buffer, pH 9.0, or 100 mM Tris-HCl, pH 8.8, 0.15 M ammonium acetate, 15% v/v 2-methyl-2,4-pentanediol, drops are suspended over 1 ml of resevroir solution, crystals appear overnight, seeds are introduced into drops conisting of 0.002 ml protein solution, 6.1 mg/ml protein, and 0.004 ml reservoir solution containing 16.5% w/v PEG 8000, 0.1 M Tris-HCl, pH 8.8, 15% v/v 2-methyl-2,4-pentanediol, 0.25 M ammonium acetate, 292 K, 2-3 weeks, X-ray diffraction structure determination and analysis at 2.20-2.28 A resolution 649099 4.2.2.19 purified recombinant enzyme, residues 25-506 corresponding to the full size mature enzyme, labeling and complexing of enzyme in crystals via soaking in cryoprotectant solution containing the heavy atom or disaccharide product in 22.5% w/v PEG 8000, 0.1 M Tris-HCl, pH 8.7, 15% v/v 2-methyl-2,4-pentanediol, and 0.25 M ammonium acetate, equilibration over 1 ml reservoir solution, complexed with disaccharide product, X-ray diffraction structure determination and analysis at 1.7 A resolution, structure modeling of the right-handed parallel beta-helix protein 652806 4.2.2.19 purified recombinant wild-type enzyme complexed with dermatan sulfate pentasaccharide and hexasaccharide, or chondroitin-4-sulfate tetrasacharide, X-ray diffraction structure determination and analysis at 1.7-1.8 A resolution, modeling of substrate binding in the active site groove 652553