An electron-bifurcating caffeyl-CoA reductase
- A low potential electron carrier ferredoxin (E0′ ≈ −500 mV) is used to fuel the only bioenergetic coupling site, a sodium-motive ferredoxin:NAD+ oxidoreductase (Rnf) in the acetogenic bacterium Acetobacterium woodii. Because ferredoxin reduction with physiological electron donors is highly endergonic, it must be coupled to an exergonic reaction. One candidate is NADH-dependent caffeyl-CoA reduction. We have purified a complex from A. woodii that contains a caffeyl-CoA reductase and an electron transfer flavoprotein. The enzyme contains three subunits encoded by the carCDE genes and is predicted to have, in addition to FAD, two [4Fe-4S] clusters as cofactor, which is consistent with the experimental determination of 4 mol of FAD, 9 mol of iron, and 9 mol of acid-labile sulfur. The enzyme complex catalyzed caffeyl-CoA-dependent oxidation of reduced methyl viologen. With NADH as donor, it catalyzed caffeyl-CoA reduction, but this reaction was highly stimulated by the addition of ferredoxin. Spectroscopic analyses revealed that ferredoxin and caffeyl-CoA were reduced simultaneously, and a stoichiometry of 1.3:1 was determined. Apparently, the caffeyl-CoA reductase-Etf complex of A. woodii uses the novel mechanism of flavin-dependent electron bifurcation to drive the endergonic ferredoxin reduction with NADH as reductant by coupling it to the exergonic NADH-dependent reduction of caffeyl-CoA.
Author: | Johannes BertschGND, Anutthaman ParthasarathyORCiDGND, Wolfgang BuckelORCiDGND, Volker MüllerORCiD |
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URN: | urn:nbn:de:hebis:30:3-768769 |
DOI: | https://doi.org/10.1074/jbc.M112.444919 |
ISSN: | 0021-9258 |
Pubmed Id: | https://pubmed.ncbi.nlm.nih.gov/23479729 |
Parent Title (English): | Journal of biological chemistry |
Publisher: | American Society for Biochemistry and Molecular Biology Publications |
Place of publication: | Bethesda, Md |
Document Type: | Article |
Language: | English |
Date of Publication (online): | 2021/01/04 |
Year of first Publication: | 2013 |
Publishing Institution: | Universitätsbibliothek Johann Christian Senckenberg |
Release Date: | 2023/11/14 |
Tag: | Acetogenesis; Bioenergetics; Electron Bifurcation; Electron Transfer; Energy Conservation; Enzyme Mechanisms; Iron-Sulfur Protein; Metalloenzymes |
Volume: | 288 |
Issue: | 16 |
Page Number: | 8 |
First Page: | 11304 |
Last Page: | 11311 |
HeBIS-PPN: | 516508571 |
Institutes: | Biowissenschaften |
Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie |
Sammlungen: | Universitätspublikationen |
Licence (German): | Creative Commons - CC BY - Namensnennung 4.0 International |