Formation of a molten-globule-like state of cytochrome c induced by high concentrations of glycerol.
The effect of glycerol on the structure of cytochrome c was investigated by circular dichroism, absorbance and EPR spectroscopy. The results obtained show that an increasing concentration of the organic solvent (70-99.2%, v/v) in aqueous-polyalcohol mixtures converts native cytochrome c into a new, low spin form through a fully reversible, two-state transition. The glycerol-stabilized form (that we call here the G state) retains native-like amounts of alpha-helix structure while rigid tertiary structure and native Fe(III)-Met(80) axial bond are lost. Analysis of data suggests a molten globule character of the G state; support to this view is afforded by the striking similarities between the spectroscopic (and, thus, structural) properties of the G state with those of the acidic molten globule of the protein (A state).
Santucci
R
R
Dipartimento di Medicina Sperimentale e Scienze Biochimiche, Universitá di Roma Tor Vergata, Rome, Italy.
Polizio
F
F
Desideri
A
A
D000818:Animals; D002942:Circular Dichroism; D003574:Cytochrome c Group / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D005990:Glycerol / Q000737:chemistry*; D006736:Horses; D011487:Protein Conformation
D003574:Cytochrome c Group; D005990:Glycerol