The role of the thioredoxin and glutaredoxin pathways in reducing protein disulfide bonds in the Escherichia coli cytoplasm

William A. Prinz, Fredrik Åslund, Arne Holmgren, Jon Beckwith

Research output: Contribution to journalArticlepeer-review

529 Scopus citations


In Escherichia coli, two pathways use NADPH to reduce disulfide bonds that form in some cytoplasmic enzymes during catalysis: the thioredoxin system, which consists of thioredoxin reductase and thioredoxin, and the glutaredoxin system, composed of glutathione reductase, glutathione, and three glutaredoxins. These systems may also reduce disulfide bonds which form spontaneously in cytoplasmic proteins when E. coli is grown aerobically. We have investigated the role of both systems in determining the thiol-disulfide balance in the cytoplasm by determining the ability of protein disulfide bonds to form in mutants missing components of these systems. We find that both the thioredoxin and glutaredoxin systems contribute to reducing disulfide bonds in cytoplasmic proteins. In addition, these systems can partially substitute for each other in vivo since double mutants missing parts of both systems generally allow substantially more disulfide bond formation than mutants missing components of just one system. Some of these double mutants were found to require the addition of a disulfide reductant to the medium to grow well aerobically. Thus, E. coli requires either a functional thioredoxin or glutaredoxin system to reduce disulfide bonds which appear after each catalytic cycle in the essential enzyme ribonucleotide reductase and perhaps to reduce non-native disulfide bonds in cytoplasmic proteins. Our results suggest the existence of a novel thioredoxin in E. coli.

Original languageEnglish (US)
Pages (from-to)15661-15667
Number of pages7
JournalJournal of Biological Chemistry
Issue number25
StatePublished - Jun 20 1997
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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