title: Impact of an easily reducible disulfide bond on the oxidative folding rate of multi-disulfide-containing proteins.
abstract: The burial of native disulfide bonds, formed within stable structure in the regeneration of multi-disulfide-containing proteins from their fully reduced states, is a key step in the folding process, as the burial greatly accelerates the oxidative folding rate of the protein by sequestering the native disulfide bonds from thiol-disulfide exchange reactions. Nevertheless, several proteins retain solvent-exposed disulfide bonds in their native structures. Here, we have examined the impact of an easily reducible native disulfide bond on the oxidative folding rate of a protein. Our studies reveal that the susceptibility of the (40-95) disulfide bond of Y92G bovine pancreatic ribonuclease A (RNase A) to reduction results in a reduced rate of oxidative regeneration, compared with wild-type RNase A. In the native state of RNase A, Tyr 92 lies atop its (40-95) disulfide bond, effectively shielding this bond from the reducing agent, thereby promoting protein oxidative regeneration. Our work sheds light on the unique contribution of a local structural element in promoting the oxidative folding of a multi-disulfide-containing protein.
authors.affiliation: Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853-1301, USA.
authors.forename: H J
authors.initials: HJ
authors.lastname: Leung
authors.forename: G
authors.initials: G
authors.lastname: Xu
authors.forename: M
authors.initials: M
authors.lastname: Narayan
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 / Q000737:chemistry* / Q000378:metabolism*; D004795:Enzyme Stability; D007700:Kinetics; D008958:Models, Molecular; D009154:Mutation / Q000235:genetics; D010084:Oxidation-Reduction; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D012259:Ribonuclease, Pancreatic / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014443:Tyrosine / Q000235:genetics / Q000378:metabolism
chemical_list: D004220:Disulfides; D014443:Tyrosine; D012259:Ribonuclease, Pancreatic