A quinol anion as catalytic intermediate coupling proton translocation with electron transfer in E. coli respiratory complex I

Abstract: 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

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch
• Notes: Frontiers in chemistry. - 9 (2021) , 672969, ISSN: 2296-2646

Contributors, Places and Time

• Event: Veröffentlichung
• (where): Freiburg
• (who): Universität
• (when): 2021
• Creator: Nuber, Franziska ; Mérono, Luca ; Oppermann, Sabrina ; Schimpf, Johannes ; Wohlwend, Daniel ; Friedrich, Thorsten

Further information

• DOI: 10.3389/fchem.2021.672969
• URN: urn:nbn:de:bsz:25-freidok-2202872
• Rights: Kein Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 25.03.2025, 1:51 PM CET