title: The promotion of self-association of horse-heart cytochrome c by hexametaphosphate anions.
abstract: In the presence of the highly charged hexametaphosphate anion, horse heart cytochrome c aggregates to form stable protein complexes. The formation of protein aggregates has been detected by high-resolution 1H-NMR spectroscopy from an increase in the linewidth of resolved ferricytochrome c resonances with hexametaphosphate concentration. Alternatively, analytical ultracentrifugation reveals protein association from the increase in apparent sedimentation coefficients of cytochrome c in the presence of equimolar hexametaphosphate. Protein aggregation is dependent on the concentration of background electrolyte since in the range 10-150 mM sodium cacodylate alternative stabilisation of dimeric and trimeric complexes was observed by both NMR and analytical ultracentrifugation. A model is proposed for the mechanism of protein aggregation caused by polyphosphate binding to the surface of cytochrome c.
authors.affiliation: Department of Biochemistry, University of Oxford, England.
authors.forename: D
authors.initials: D
authors.lastname: Whitford
authors.forename: D W
authors.initials: DW
authors.lastname: Concar
authors.forename: R J
authors.initials: RJ
authors.lastname: Williams
mesh_terms: D000818:Animals; D002101:Cacodylic Acid / Q000494:pharmacology; D003574:Cytochrome c Group / Q000378:metabolism*; D006736:Horses; D006859:Hydrogen; D007700:Kinetics; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009206:Myocardium / Q000378:metabolism; D009994:Osmolar Concentration; D010710:Phosphates / Q000494:pharmacology*; D014461:Ultracentrifugation / Q000379:methods
chemical_list: D003574:Cytochrome c Group; D046911:Macromolecular Substances; D010710:Phosphates; C005035:hexametaphosphate; D006859:Hydrogen; D002101:Cacodylic Acid