Journal
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
Volume 54, Issue 9, Pages 2844-2848Publisher
WILEY-V C H VERLAG GMBH
DOI: 10.1002/anie.201410967
Keywords
bioenergetics; electron tunneling; enzyme kinetics; metalloenzymes; reaction mechanisms
Categories
Funding
- Netherlands Organization for Scientific Research (NWO)
- Deutsche Forschungsgemeinschaft (DFG)
Ask authors/readers for more resources
Respiratory complex I converts the free energy of ubiquinone reduction by NADH into a proton motive force, a redox reaction catalyzed by flavin mononucleotide(FMN) and a chain of seven iron-sulfur centers. Electron transfer rates between the centers were determined by ultrafast freeze-quenching and analysis by EPR and UV/Vis spectroscopy. The complex rapidly oxidizes three NADH molecules. The electron-tunneling rate between the most distant centers in the middle of the chain depends on the redox state of center N2 at the end of the chain, and is sixfold slower when N2 is reduced. The conformational changes that accompany reduction of N2 decrease the electronic coupling of the longest electron-tunneling step. The chain of iron-sulfur centers is not just a simple electron-conducting wire; it regulates the electron-tunneling rate synchronizing it with conformation-mediated proton pumping, enabling efficient energy conversion. Synchronization of rates is a principle means of enhancing the specificity of enzymatic reactions.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available