Structure of human carbonic anhydrase B: I. Crystallization and heavy atom modifications

Human carbonic anhydrase B has been crystallized from 2.3 M-ammonium sulphate solution at pH 8.7. A method for reproducible crystallization is presented. The crystals are suitable for high-resolution X-ray diffraction studies. They belong to the orthorhombic space group P 212121 with cell dimensions a = 81.5 Å, B = 73.6 Å, C = 37.1Å. The position of the essential zinc ion has been established from two projections. The zinc ion has been replaced by mercury to form one of the heavy atom derivatives