5.3.2.5 | activated wild-type enolase, carboxylated on Lys173, with Mg2+ alone, or Mg2+, and HCO3-, or Mg2+ and substrate 2,3-diketohexane 1-phosphate, and of the selenomethionine-substituted enzyme variant, hanging drop method, 10-15 mg/ml protein in 20 mM Tris-HCl, pH 7.9, 100 mM NaCl, and 5-10 mM MgCl2, 100 mM NaCl, and 1-5 mM NaHCO3, mixed with 24% PEG 3350, 0.1 M Tris-HCl, pH 8.5, and 0.2 M ammonium acetate as precipitant for the crystals of wild-type enzyme with Mg2+, or 25% PEG 3350, 0.1 M HEPES, pH 7.5, and 0.2 M ammonium acetate as precipitant for the other crystal variants, room temperature, 6 days, X-ray diffraction structure determination and analysis at 1.7 A resolution, molecular replacement |