A Quinol Anion as Catalytic Intermediate Coupling Proton Translocation With Electron Transfer in E. coli Respiratory Complex I
| Autor: | Daniel Wohlwend, Luca Mérono, Thorsten Friedrich, Johannes Schimpf, Franziska Nuber, Sabrina Oppermann |
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| Rok vydání: | 2021 |
| Předmět: |
proton-coupled electron transfer
Stereochemistry Kinetics respiratory complex I bioenergetics 010402 general chemistry 01 natural sciences Redox 03 medical and health sciences chemistry.chemical_compound Electron transfer Oxidoreductase Escherichia coli Piericidin A QD1-999 030304 developmental biology chemistry.chemical_classification 0303 health sciences biology NADH dehydrogenase quinone chemistry General Chemistry 0104 chemical sciences Quinone Chemistry chemistry biology.protein Proton-coupled electron transfer |
| Zdroj: | Frontiers in Chemistry, Vol 9 (2021) |
| ISSN: | 2296-2646 |
| DOI: | 10.3389/fchem.2021.672969 |
| Popis: | Energy-converting NADH:ubiquinone oxidoreductase, respiratory complex I, plays a major role in cellular energy metabolism. It couples NADH oxidation and quinone reduction with the translocation of protons across the membrane, thus contributing to the protonmotive force. Complex I has an overall L-shaped structure with a peripheral arm catalyzing electron transfer and a membrane arm engaged in proton translocation. Although both reactions are arranged spatially separated, they are tightly coupled by a mechanism that is not fully understood. Using redox-difference UV-vis spectroscopy, an unknown redox component was identified in Escherichia coli complex I as reported earlier. A comparison of its spectrum with those obtained for different quinone species indicates features of a quinol anion. The re-oxidation kinetics of the quinol anion intermediate is significantly slower in the D213GH variant that was previously shown to operate with disturbed quinone chemistry. Addition of the quinone-site inhibitor piericidin A led to strongly decreased absorption peaks in the difference spectrum. A hypothesis for a mechanism of proton-coupled electron transfer with the quinol anion as catalytically important intermediate in complex I is discussed. |
| Databáze: | OpenAIRE |
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