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A simple energy-conserving system: proton reduction coupled to proton translocation
Rajat Sapra1, Karine Bagramyan, Michael W W Adams
1Department of Biochemistry and Molecular Biology, Center for Metalloenzyme Studies, University of Georgia, Athens, GA 30602-7229, USA.
Summary
Pyrococcus furiosus conserves energy via hydrogen production, coupling ATP synthesis to a proton-motive force using a unique hydrogenase enzyme. This explains its high growth yields and unusual metabolism.
Area of Science:
- Biochemistry
- Microbiology
- Bioenergetics
Background:
- Oxidative phosphorylation typically uses membrane-bound complexes to reduce external electron acceptors.
- Pyrococcus furiosus, a hyperthermophilic archaeon, possesses a distinct anaerobic respiratory system.
Purpose of the Study:
- To investigate the energy conservation mechanism in Pyrococcus furiosus.
- To elucidate the role of its unique hydrogenase-based respiratory system.
Main Methods:
- Studied ATP synthesis coupled to proton-motive force in P. furiosus membrane vesicles.
- Analyzed the function of the membrane-bound hydrogenase and ferredoxin.
Main Results:
- Demonstrated direct coupling of hydrogen gas production to ATP synthesis via proton-motive force.
- Showed ferredoxin acts as an electron donor to protons, producing hydrogen.
- Explained energy conservation in P. furiosus's unusual glycolytic pathway.
Conclusions:
- P. furiosus utilizes a simple respiratory mechanism for energy conservation through hydrogen production.
- This mechanism accounts for higher growth yields and provides insights into the evolution of respiration and the origin of life.