Structural highlights
Function
CARE_ACEWD Caffeyl-CoA reductase-Etf complex catalyzes the reduction of caffeyl-CoA to yield hydrocaffeyl-CoA. It couples the endergonic ferredoxin reduction with NADH as reductant to the exergonic reduction of caffeoyl-CoA with the same reductant. It uses the mechanism of electron bifurcation to overcome the steep energy barrier in ferredoxin reduction. The electron transfer flavoprotein (Etf) mediates the electron transfer between the different donors and acceptors. The iron-sulfur cluster may be involved in electron transport, possibly in the intramolecular electron transfer from the Etf protein subunit to the caffeyl-CoA reductase subunit inside the complex. The complex can also reduce 4-coumaroyl-CoA and feruloyl-CoA.[1]
Publication Abstract from PubMed
Flavin-based electron bifurcation (FBEB) is a recently discovered mode of energy coupling in anaerobic microorganisms. The electron-bifurcating caffeyl-CoA reductase (CarCDE) catalyzes the reduction of caffeyl-CoA and ferredoxin by oxidizing NADH. The 3.5 A structure of the heterododecameric Car(CDE)4 complex of Acetobacterium woodii, presented here, reveals compared to other electron transferring flavoprotein/ acyl dehydrogenase family members an additional ferredoxin-like domain with two [4Fe-4S] clusters N-terminally fused to CarE. It might serve, in vivo, as specific adaptor for the physiological electron acceptor. Kinetic analysis of a CarCDE(Fd) complex indicates the bypassing of the ferredoxin domain by artificial electron acceptors. Site-directed mutagenesis studies substantiated the crucial role of the C-terminal arm of CarD and of ArgE203 hydrogen-bonded to the bifurcating FAD for FBEB. This article is protected by copyright. All rights reserved.
Molecular basis of the flavin-based electron-bifurcating caffeyl-CoA reductase reaction.,Demmer JK, Bertsch J, Oppinger C, Wohlers H, Kayastha K, Demmer U, Ermler U, Muller V FEBS Lett. 2018 Jan 11. doi: 10.1002/1873-3468.12971. PMID:29325219[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Bertsch J, Parthasarathy A, Buckel W, Muller V. An electron-bifurcating caffeyl-CoA reductase. J Biol Chem. 2013 Apr 19;288(16):11304-11. doi: 10.1074/jbc.M112.444919. Epub, 2013 Mar 11. PMID:23479729 doi:http://dx.doi.org/10.1074/jbc.M112.444919
- ↑ Demmer JK, Bertsch J, Oppinger C, Wohlers H, Kayastha K, Demmer U, Ermler U, Muller V. Molecular basis of the flavin-based electron-bifurcating caffeyl-CoA reductase reaction. FEBS Lett. 2018 Jan 11. doi: 10.1002/1873-3468.12971. PMID:29325219 doi:http://dx.doi.org/10.1002/1873-3468.12971
