Mechanistic insights into energy conservation by flavin-based electron bifurcation
- Lubner, Carolyn E. [ Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA ]
- Mulder, David W. [ Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA ]
- King, Paul W. [ Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA ]
- Jennings, David P. [ School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA ]
- Jones, Anne K. [ School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA ]
- Schut, Gerrit J. [ Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA ]
- Nguyen, Diep M. [ Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA ]
- Lipscomb, Gina L. [ Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA ]
- Adams, Michael W. W. [ Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA ]
- Zadvornyy, Oleg A. [ Montana State University: Chemistry & Biochemistry ]
- Tokmina-Lukaszewska, Monika [ Montana State University: Chemistry & Biochemistry ]
- Berry, Luke [ Montana State University: Chemistry & Biochemistry ]
- Bothner, Brian [ Montana State University: Chemistry & Biochemistry ]
- Peters, John W. [ Montana State University: Chemistry & Biochemistry ] [ Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA ]
- Hoben, John P. [ Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA ]
- Miller, Anne-Frances [ Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA ]
The recently realized biochemical phenomenon of energy conservation through electron bifurcation provides biology with an elegant means to maximize utilization of metabolic energy. The mechanism of coordinated coupling of exergonic and endergonic oxidation–reduction reactions by a single enzyme complex has been elucidated through optical and paramagnetic spectroscopic studies revealing unprecedented features. Pairs of electrons are bifurcated over more than 1 volt of electrochemical potential by generating a low-potential, highly energetic, unstable flavin semiquinone and directing electron flow to an iron–sulfur cluster with a highly negative potential to overcome the barrier of the endergonic half reaction. The unprecedented range of thermodynamic driving force that is generated by flavin-based electron bifurcation accounts for unique chemical reactions that are catalyzed by these enzymes.