Characterization of DsbC, a periplasmic protein of Erwinia chrysanthemi and Escherichia coli with disulfide isomerase activity

EMBO J. 1994 Apr 15;13(8):2007-12.


We identified and characterized an Erwinia chrysanthemi gene able to complement an Escherichia coli dsbA mutation that prevents disulfide bond formation in periplasmic proteins. This gene, dsbC, codes for a 24 kDa periplasmic protein that contains a characteristic active site sequence of disulfide isomerases, Phe-X-X-X-X-Cys-X-X-Cys. Besides the active site, DsbC has no homology with DsbA, thioredoxin or eukaryotic protein disulfide isomerase and it could define a new subfamily of disulfide isomerases. Purified DsbC protein is able to catalyse insulin oxidation in a dithiothreitol dependent manner. The E.coli gene xprA codes for a protein functionally equivalent to DsbC. The in vivo function of DsbC seems to be the formation of disulfide bonds in proteins. The presence of XprA could explain the residual disulfide isomerase activity existing in dsbA mutants. Re-oxidation of XprA does not seem to occur through DsbB, the protein that probably re-oxidizes DsbA.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cell Compartmentation
  • Cloning, Molecular
  • Escherichia coli / enzymology
  • Escherichia coli / genetics*
  • Genes, Bacterial / genetics
  • Genetic Complementation Test
  • Isomerases / genetics*
  • Membrane Proteins / genetics*
  • Molecular Sequence Data
  • Mutation
  • Pectobacterium chrysanthemi / enzymology
  • Pectobacterium chrysanthemi / genetics*
  • Protein Disulfide-Isomerases
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid


  • Membrane Proteins
  • Isomerases
  • Protein Disulfide-Isomerases

Associated data

  • GENBANK/X76687