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Molecular basis of the flavin‐based electron‐bifurcating caffeyl‐CoA reductase reaction
Author(s) -
Demmer Julius K.,
Bertsch Johannes,
Öppinger Christian,
Wohlers Hannah,
Kayastha Kanwal,
Demmer Ulrike,
Ermler Ulrich,
Müller Volker
Publication year - 2018
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.12971
Subject(s) - ferredoxin , flavin group , electron acceptor , flavoprotein , chemistry , electron transfer , electron transport chain , ferredoxin—nadp(+) reductase , electron donor , stereochemistry , crystallography , photochemistry , biochemistry , enzyme , catalysis
Flavin‐based electron bifurcation ( FBEB ) is a recently discovered mode of energy coupling in anaerobic microorganisms. The electron‐bifurcating caffeyl‐CoA reductase (Car CDE ) catalyzes the reduction of caffeyl‐CoA and ferredoxin by oxidizing NADH . The 3.5 Å 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 Car CDE (∆Fd) complex indicates the bypassing of the ferredoxin‐like 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.