title: DsbD-catalyzed transport of electrons across the membrane of Escherichia coli.
abstract: Dsb proteins catalyze folding and oxidation of polypeptides in the periplasm of Escherichia coli. DsbC reduces wrongly paired disulfides by transferring electrons from its catalytic dithiol motif (98)CGYC. Genetic evidence suggests that recycling of this motif requires at least three proteins, the cytoplasmic thioredoxin reductase (TrxB) and thioredoxin (TrxA) as well as the DsbD membrane protein. We demonstrate here that electrons are transferred directly from thioredoxin to DsbD and from DsbD to DsbC. Three cysteine pairs within DsbD undergo reversible disulfide rearrangements. Our results suggest a novel mechanism for electron transport across membranes whereby electrons are transferred sequentially from cysteine pairs arranged in a thioredoxin-like motif (CXXC) to a cognate reactive disulfide.
authors.affiliation: Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California 90095, USA.
authors.forename: R
authors.initials: R
authors.lastname: Krupp
authors.forename: C
authors.initials: C
authors.lastname: Chan
authors.forename: D
authors.initials: D
authors.lastname: Missiakas
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004220:Disulfides / Q000378:metabolism; D004579:Electron Transport / Q000502:physiology*; D004926:Escherichia coli / Q000378:metabolism*; D019704:Protein Disulfide-Isomerases / Q000378:metabolism*
chemical_list: D004220:Disulfides; D019704:Protein Disulfide-Isomerases