Crystal structure of human erythrocyte carbonic anhydrase B. Three-dimensional structure at a nominal 2.2-Å resolution

The three-dimensional structure of carbonic anhydrase B (EC 4,2,1,1; carbonate hydro-lyase) from human erythrocytes has been determined to high resolution. Parallel and antiparallel pleated sheet makes up the predominant secondary structure of the enzyme. The tertiary structure is unique for its folding and is very similar to the structure is unique for its folding and is very similar to the structure of the isoenzyme, human erythrocyte carbonic anhydrase C. The essential metal ion, zinc, is firmly bound to the enzyme through three histidyl ligands and located at the bottom of a 12-Å deep conical cavity. The zinc ligands are involved in a number of hydrogen bond formations with residues in the immediate vicinity of the active site cavity. Some of the similarities and differences in the sidechain orientation and active site topography of the two isoenzymes are also discussed

Crystallization and crystallographic data of notexin: a neurotoxic basic phospholipase A from the venom of Australian tiger snake Notechis scutatus scutatus

Crystals of notexin, a presynaptic neurotoxin from the venom of Notechis scutatus scutatus (Australian tiger snake) have been grown in 1.3 M ammonium sulphate 0.05 M Tris-H2SO4 pH 8.5. The crystals diffract well to at least a resolution of 1.8 Å. There are 6 molecules in the unit cell of dimensions: a=b=75.03 Å. c= 49.04 Å . γ=120°. The space group is P312 1 or P322 1

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 The zinc ion has been replaced by mercury to form one of the heavy atom derivatives