Transient Dimer in The Refolding Kinetics of Cytochrome C Characterized by Small-angle X-ray Scattering

Document Type

Article

Publication Date

1999

Keywords

Imidazoles, Kinetics, Oligomers, Scattering, X-ray Scattering

Digital Object Identifier (DOI)

https://doi.org/10.1021/bi991337k

Abstract

The equilibrium unfolding and the kinetic refolding of cytochrome c (Cyt c) in the presence of imidazole were studied with small-angle X-ray scattering (SAXS). The equilibrium unfolding experiments showed the radius of gyration, Rg, of native Cyt c to swell ∼1 Å with the addition of imidazole. The thermodynamic parameter m also reflects an expansion of the protein as its lower value demonstrates an increase in solvent-accessible surface area over that of native Cyt c in the absence of imidazole. Refolding was studied in the presence of imidazole as it prevents misligated intermediate states from forming during the refolding process, simplifying the kinetics, and making them easier to resolve. Time-resolved decreases in the forward scattering amplitude, I(0), demonstrated the transient formation of an aggregated intermediate. Final protein and denaturant concentrations were varied in the refolding kinetics, and the singular value decomposition (SVD) method was employed to characterize the associated state. This state was determined to be a dimer, with properties consistent with a molten globule.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Biochemistry, v. 38, issue 46, p. 15352-15359

Share

COinS