Bacillus subtilis ResA is a thiol-disulfide oxidoreductase involved in cytochrome c synthesis
Author
Summary, in English
Covalent attachment of heme to apocytochromes c in bacteria occurs on the outside of the cytoplasmic membrane and requires two reduced cysteinyls at the heme binding site. A constructed ResA-deficient Bacillus subtilis strain was found to lack c-type cytochromes. Cytochrome c synthesis was restored in the mutant by: (i) in trans expression of resA; (ii) deficiency in BdbD, a thioldisulfide oxidoreductase that catalyzes formation of an intramolecular disulfide bond in apocytochrome c after transfer of the polypeptide across the cytoplasmic membrane; or (iii) by addition of the reductant dithiothreitol to the growth medium. In vivo studies of ResA showed that it is membrane-associated with its thioredoxin-like domain on the outside of the cytoplasmic membrane. Analysis of a soluble form of the protein revealed two redox reactive cysteine residues with a midpoint potential of about -340 mV at pH 7. We conclude that ResA, probably together with another thiol-disulfide oxidoreductase, CcdA, is required for the reduction of the cysteinyls in the heme binding site of apocytochrome c.
Department/s
Publishing year
2003
Language
English
Pages
17852-17858
Publication/Series
Journal of Biological Chemistry
Volume
278
Issue
20
Document type
Journal article
Publisher
American Society for Biochemistry and Molecular Biology
Topic
- Microbiology
- Biochemistry and Molecular Biology
Status
Published
ISBN/ISSN/Other
- ISSN: 1083-351X