title: Structure-function relationship of reduced cytochrome c probed by complete solution structure determination in 30% acetonitrile/water solution.
abstract: The complete solution structure of ferrocytochrome c in 30% acetonitrile/70% water has been determined using high-field 1D and 2D (1)H NMR methods and deposited in the Protein Data Bank with codes 1LC1 and 1LC2. This is the first time a complete solution protein structure has been determined for a protein in nonaqueous media. Ferrocyt c retains a native protein secondary structure (five alpha-helices and two omega loops) in 30% acetonitrile. H18 and M80 residues are the axial heme ligands, as in aqueous solution. Residues believed to be axial heme ligands in the alkaline-like conformers of ferricyt c, specifically H33 and K72, are positioned close to the heme iron. The orientations of both heme propionates are markedly different in 30% acetonitrile/70% water. Comparative structural analysis of reduced cyt c in 30% acetonitrile/70% water solution with cyt c in different environments has given new insight into the cyt c folding mechanism, the electron transfer pathway, and cell apoptosis.
authors.affiliation: Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA.
authors.forename: Sivashankar G
authors.initials: SG
authors.lastname: Sivakolundu
authors.affiliation: Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA. p.mabrouk@neu.edu.
authors.forename: Patricia Ann
authors.initials: PA
authors.lastname: Mabrouk
mesh_terms: D000097:Acetonitriles; D000595:Amino Acid Sequence; D000818:Animals; D003574:Cytochrome c Group / Q000737:chemistry*; D004735:Energy Transfer; D006736:Horses; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012996:Solutions; D013329:Structure-Activity Relationship; D014867:Water
chemical_list: D000097:Acetonitriles; D003574:Cytochrome c Group; D012996:Solutions; D014867:Water; C032159:acetonitrile