title: Preliminary X-ray studies of the tetra-heme cytochrome c3 and the octa-heme cytochrome c3 from Desulfovibrio gigas.
abstract: A tetra-heme and an octa-heme cytochrome c3 from the sulfate bacterium Desulfovibrio gigas have been crystallized. Diffraction quality crystals of the tetra-heme cytochrome are obtained from solution by the addition of polyethylene glycol at pH 6.5. The crystals are orthorhombic, space group P2(1)2(1)2 with unit cell parameters a = 42.27 A, b = 52.54 A and c = 52.83 A. The octa-heme cytochrome crystals develop from low ionic strength solutions of phosphate or Tris-Cl in the pH range 6.2-7.6. The crystals belong to the trigonal system, space group P3(1) or the enantiomorph P3(2), with unit cell parameters a = b = 57.4 A, c = 97.3 A, gamma = 120 degrees. Single crystal diffraction studies of the structures of these two low-potential cytochromes are in progress.
mesh_terms: D003574:Cytochrome c Group / Q000302:isolation & purification; D003901:Desulfovibrio / Q000378:metabolism*; D011092:Polyethylene Glycols; D011487:Protein Conformation; D014961:X-Ray Diffraction
chemical_list: D003574:Cytochrome c Group; D011092:Polyethylene Glycols; C017165:cytochrome c(3)