3.4.24.70 | purified enzyme TOP2 bound to 4-azido-salicylate, sitting-drop vapor-diffusion method, mixing of 40 mg/ml protein in 20 mM Tris, pH 8.5, 200 mM NaCl, 5 mM DTT, 5% v/v glycerol, with reservoir solution consisting of 220 mM ammonium acetate, 20% w/v PEG 3350, 20°C, X-ray diffraction structure determination and analysis at 3.0 A resolution |