title: Biochemical basis of oxidative protein folding in the endoplasmic reticulum.
abstract: The endoplasmic reticulum (ER) supports disulfide bond formation by a poorly understood mechanism requiring protein disulfide isomerase (PDI) and ERO1. In yeast, Ero1p-mediated oxidative folding was shown to depend on cellular flavin adenine dinucleotide (FAD) levels but not on ubiquinone or heme, and Ero1p was shown to be a FAD-binding protein. We reconstituted efficient oxidative folding in vitro using FAD, PDI, and Ero1p. Disulfide formation proceeded by direct delivery of oxidizing equivalents from Ero1p to folding substrates via PDI. This kinetic shuttling of oxidizing equivalents could allow the ER to support rapid disulfide formation while maintaining the ability to reduce and rearrange incorrect disulfide bonds.
authors.affiliation: Howard Hughes Medical Institute, Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94143, USA.
authors.forename: B P
authors.initials: BP
authors.lastname: Tu
authors.forename: S C
authors.initials: SC
authors.lastname: Ho-Schleyer
authors.forename: K J
authors.initials: KJ
authors.lastname: Travers
authors.forename: J S
authors.initials: JS
authors.lastname: Weissman
mesh_terms: D001665:Binding Sites; D002268:Carboxypeptidases / Q000737:chemistry / Q000378:metabolism; D043402:Cathepsin A; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004220:Disulfides / Q000737:chemistry; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism*; D008861:Microsomes / Q000378:metabolism; D009154:Mutation; D010084:Oxidation-Reduction; D050862:Oxidoreductases Acting on Sulfur Group Donors; D019704:Protein Disulfide-Isomerases / Q000235:genetics / Q000378:metabolism*; D017510:Protein Folding; D012259:Ribonuclease, Pancreatic / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D004220:Disulfides; D006023:Glycoproteins; D029701:Saccharomyces cerevisiae Proteins; D005182:Flavin-Adenine Dinucleotide; D050862:Oxidoreductases Acting on Sulfur Group Donors; C113186:ERO1 protein, S cerevisiae; D012259:Ribonuclease, Pancreatic; D002268:Carboxypeptidases; D043402:Cathepsin A; D019704:Protein Disulfide-Isomerases; D005978:Glutathione