title: Formation of native structure by intermolecular thiol-disulfide exchange reactions without oxidants in the folding of bovine pancreatic ribonuclease A.
abstract: It has been shown previously that the oxidative folding of bovine pancreatic ribonuclease A proceeds through parallel pathways with two major native-like three-disulfide (3S) intermediates. We show here that, under some conditions, the native disulfide bonds can also be regenerated through disproportionation reactions; in other words, the protein can serve as its own redox reagent. The results also show that disulfide species of the unstructured 3S ensemble have a strong propensity to participate in intermolecular interactions. These interactions are favored at high protein concentration, temperature and pH, and lead to formation of the native structure during disulfide reshuffling in the rate-determining step.
authors.affiliation: Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853-1301, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Song
authors.forename: H A
authors.initials: HA
authors.lastname: Scheraga
mesh_terms: D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D004220:Disulfides / Q000378:metabolism*; D004229:Dithiothreitol / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D016877:Oxidants / Q000378:metabolism*; D010084:Oxidation-Reduction; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D012259:Ribonuclease, Pancreatic / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D012997:Solvents; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D013696:Temperature
chemical_list: D004220:Disulfides; D016877:Oxidants; D012997:Solvents; D013438:Sulfhydryl Compounds; D012259:Ribonuclease, Pancreatic; D005978:Glutathione; D004229:Dithiothreitol