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Characterization of DsbC, a periplasmic protein of Erwinia chrysanthemi and Escherichia coli with disulfide isomerase activity.
Author(s) -
Shevchik V.E.,
Condemine G.,
RobertBaudouy J.
Publication year - 1994
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1994.tb06470.x
Subject(s) - escherichia coli , biology , microbiology and biotechnology , periplasmic space , erwinia , cis trans isomerases , dsba , genetics , gene , peptidylprolyl isomerase , isomerase
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.