title: Tuna cytochrome c at 2.0 A resolution. II. Ferrocytochrome structure analysis.
abstract: The x-ray crystal structure analysis of tuna ferrocytochrome c has been extended from 2.45 to 2.0 A resolution. The overall folding is unchanged and is the same as has been reported for tuna ferricytochrome c (Swanson R., Trus, B.L., Mandel, N., Mandel, G., Kallai, O.B., and Dickerson, R.E. (1977) J. Biol. Chem. 252, 759-755). No significant structural differences are observed between oxidation states. Difference map studies using reoxidized crystals of ferrocytochrome c confirm the absence of a conformation change. A detailed analysis of hydrogen bonding shows the presence of six beta or 310 bends of type II with obligatory glycines in the 3rd residue position. This explains 6 of the 10 nearly invariant glycines in the molecule. Close packing contacts account for three more, and only the invariant glycine 1 remains a mystery.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D003574:Cytochrome c Group; D005583:Fourier Analysis; D008628:Mercury; D008958:Models, Molecular; D009206:Myocardium / Q000201:enzymology; D010984:Platinum; D011485:Protein Binding; D011487:Protein Conformation; D014413:Tuna; D014961:X-Ray Diffraction
chemical_list: D003574:Cytochrome c Group; D010984:Platinum; D008628:Mercury