title: Denaturation and renaturation of self-assembled yeast iso-1-cytochrome c on Au.
abstract: We have made surface plasmon resonance (SPR) measurements of yeast iso-1-cytochrome c (Cyt c) on a gold surface. Angle-resolved SPR curves are recorded as a function of urea concentration before and after self-assembly of the Cyt c. Exposure to a urea solution causes denaturation of Cyt c, which shifts the minimum in the SPR curve to a larger angle and decreases the signal amplitude. The Gibbs free energy change for denaturation of the protein on Au is calculated from the change of the SPR signal amplitude with urea concentration. We find that (1) Cyt c can be reversibly denatured and renatured, depending on the urea concentration, and (2) the Gibbs free energy change for denaturation of Cyt c on Au surface in water, DeltaG degrees (water), is 1.5 kcal/mol, which is approximately 4 times less than that in bulk solution.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
authors.forename: Soonwoo
authors.initials: S
authors.lastname: Chah
authors.forename: Challa V
authors.initials: CV
authors.lastname: Kumar
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Hammond
authors.forename: Richard N
authors.initials: RN
authors.lastname: Zare
mesh_terms: D045304:Cytochromes c / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D011489:Protein Denaturation; D020673:Protein Renaturation; D017434:Protein Structure, Tertiary; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry*; D013329:Structure-Activity Relationship; D020349:Surface Plasmon Resonance / Q000379:methods*; D013816:Thermodynamics; D014508:Urea / Q000494:pharmacology
chemical_list: C014059:CYC1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D006046:Gold; D014508:Urea; D045304:Cytochromes c