1.14.13.29 | purified recombinant His-tagged wild-type enzyme, sitting drop vapor diffusion method, mixing equal volumes of protein solution and reservoir solution. The reservoir solution contains 0.1 M Tris, pH 7.25, 1.5 M (NH4)2SO4, and 4% v/v glycerol, diffraction-quality crystals of PnpA1 appear within 5 days at 20°C, X-ray diffraction structure determination and analysis at 2.5 A resolution |