title: Reductive unfolding of serum albumins uncovered by Raman spectroscopy.
abstract: The reductive unfolding of bovine serum albumin (BSA) and human serum albumin (HSA) induced by dithiothreitol (DTT) is investigated using Raman spectroscopy. The resolution of the S-S Raman band into both protein and oxidized DTT contributions provides a reliable basis for directly monitoring the S-S bridge exchange reaction. The related changes in the protein secondary structure are identified by analyzing the protein amide I Raman band. For the reduction of one S-S bridge of BSA, a mean Gibbs free energy of -7 kJ mol(-1) is derived by studying the reaction equilibrium. The corresponding value for the HSA S-S bridge reduction is -2 kJ mol(-1). The reaction kinetics observed via the S-S or amide I Raman bands are identical giving a reaction rate constant of (1.02 +/- 0.11) M(-1) s(-1) for BSA. The contribution of the conformational Gibbs free energy to the overall Gibbs free energy of reaction is further estimated by combining experimental data with ab initio calculations.
authors.affiliation: University of Franche-Comte, Laboratoire de Physico-Chimie et Rayonnement-Alain Chambaudet, UMR EA E4, 16 route de Gray, 25030 Besancon, France.
authors.forename: Catalina
authors.initials: C
authors.lastname: David
authors.forename: Sarah
authors.initials: S
authors.lastname: Foley
authors.forename: Christophe
authors.initials: C
authors.lastname: Mavon
authors.forename: Mironel
authors.initials: M
authors.lastname: Enescu
mesh_terms: D000818:Animals; D002417:Cattle; D003198:Computer Simulation; D004220:Disulfides / Q000737:chemistry; D006801:Humans; D008954:Models, Biological; D010084:Oxidation-Reduction; D011489:Protein Denaturation; D017510:Protein Folding; D012709:Serum Albumin / Q000737:chemistry*; D013059:Spectrum Analysis, Raman
chemical_list: D004220:Disulfides; D012709:Serum Albumin