1.5.3.10 | purified recombinant wild-type enzyme, sitting-drop vapour diffusion method, 0.004 ml of protein solution containing 15 mg/ml protein, mixed with 0.002 ml reservoir solution containing 15% PEG 5000 monomethylether, 0.2 M MgCl2, and 0.1 M HEPES, pH 7.5, magnesium salt can be exchanged for acetate, for complexing the crystals are soaked in a solution containing folic or folinic acid in 15% PEG 5000 monomethylether and 0.3 M NaCl for 10 min, X-ray diffraction structure determination and analysis at 1.60 A resolution |