Reaction: butanoyl-CoA + 2 NAD+ + 2 reduced ferredoxin [iron-sulfur] cluster = (E)-but-2-enoyl-CoA + 2 NADH + 2 oxidized ferredoxin [iron-sulfur] cluster
Glossary: (E)-but-2-enoyl-CoA = crotonyl-CoA
Other name(s): bifurcating butyryl-CoA dehydrogenase; butyryl-CoA dehydrogenase/Etf complex; Etf-Bcd complex; bifurcating butanoyl-CoA dehydrogenase; butanoyl-CoA dehydrogenase/Etf complex; butanoyl-CoA dehydrogenase (NAD+, ferredoxin)
Systematic name: butanoyl-CoA:NAD+, ferredoxin oxidoreductase
Comments: The enzyme is a complex of a flavin-containing dehydrogenase component (Bcd) and an electron-transfer flavoprotein dimer (EtfAB). The enzyme complex, isolated from the bacteria Acidaminococcus fermentans and butanoate-producing Clostridia species, couples the exergonic reduction of (E)-but-2-enoyl-CoA to butanoyl-CoA by NADH to the endergonic reduction of ferredoxin by NADH, using electron bifurcation to overcome the steep energy barrier in ferredoxin reduction.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Li, F., Hinderberger, J., Seedorf, H., Zhang, J., Buckel, W. and Thauer, R.K. Coupled ferredoxin and crotonyl coenzyme A (CoA) reduction with NADH catalyzed by the butyryl-CoA dehydrogenase/Etf complex from Clostridium kluyveri. J. Bacteriol. 190 (2008) 843-850. [PMID: 17993531]
2. Aboulnaga el,-H., Pinkenburg, O., Schiffels, J., El-Refai, A., Buckel, W. and Selmer, T. Effect of an oxygen-tolerant bifurcating butyryl coenzyme A dehydrogenase/electron-transferring flavoprotein complex from Clostridium difficile on butyrate production in Escherichia coli. J. Bacteriol. 195 (2013) 3704-3713. [PMID: 23772070]
3. Chowdhury, N.P., Mowafy, A.M., Demmer, J.K., Upadhyay, V., Koelzer, S., Jayamani, E., Kahnt, J., Hornung, M., Demmer, U., Ermler, U. and Buckel, W. Studies on the mechanism of electron bifurcation catalyzed by electron transferring flavoprotein (Etf) and butyryl-CoA dehydrogenase (Bcd) of Acidaminococcus fermentans. J. Biol. Chem. 289 (2014) 5145-5157. [PMID: 24379410]
4. Chowdhury, N.P., Kahnt, J. and Buckel, W. Reduction of ferredoxin or oxygen by flavin-based electron bifurcation in Megasphaera elsdenii. FEBS J. 282 (2015) 3149-3160. [PMID: 25903584]