Four cysteines of the membrane protein DsbB act in concert to oxidize its substrate DsbA

Hiroshi Kadokura, Jon Beckwith

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82 Citations (Scopus)


Protein disulfide bond formation in Escherichia coli is catalyzed by the periplasmic protein DsbA. A cytoplasmic membrane protein DsbB maintains DsbA in the oxidized state by transferring electrons from DsbA to quinones in the respiratory, chain. Here we show that DsbB activity can be reconstituted by coexpression of N- and C-terminal fragments of the protein, each containing one of its redox-active disulfide bonds. This system has allowed us (i) to demonstrate that the two DsbB redox centers interact directly through a disulfide bond formed between the two DsbB domains and (ii) to identify the specific cysteine residues involved in this covalent interaction. Moreover, we are able to capture an intermediate in the process of electron transfer from one redox center to the other. These results lead us to propose a model that describes how the cysteines cooperate in the early stages of oxidation of DsbA. DsbB appears to adopt a novel mechanism to oxidize DsbA, using its two pairs of cysteines in a coordinated reaction to accept electrons from the active cysteines in DsbA.

Original languageEnglish
Pages (from-to)2354-2363
Number of pages10
JournalEMBO Journal
Issue number10
Publication statusPublished - 2002 May 15
Externally publishedYes


  • Disulfide bond formation
  • DsbB
  • Electron transfer
  • Escherichia coil
  • Oxidative protein folding

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)


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