Berlin 2018 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 12: Computational Biophysics I
BP 12.12: Vortrag
Dienstag, 13. März 2018, 12:45–13:00, H 1058
Terminal Electron-Proton Transfer Dynamics coupled to Quinone reduction in Respiratory Complex I — •Ana Patricia Gamiz-Hernandez1, Alexander Jussupow1, Mikael P. Johansson2, and Ville R. I. Kaila1 — 1Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, D-85747, Garching, Germany — 2Department of Chemistry, University of Helsinki, P. O. Box 55, FI-00014 Helsinki, Finland
Complex I (NADH:ubiquinone oxidoreductase) contains 8-9 iron sulfur clusters (ISC) in its hydrophilic domain responsible of transferring two electrons from NADH/FMN couple to the quinone binding site, thus initiating the signal that triggers proton pump across its membrane. Although the exact coupling for this long-range proton-electron transfer process remains unclear, emerging data indicates that the initial quinone (Q) reduction to quinol (QH2) process plays a central role in activating the proton pumping machinery. In order to probe the energetics, dynamics, and molecular mechanism for the proton-coupled electron transfer (PCET) process linked to Q reduction, we employ here multi-scale quantum and classical molecular simulations, to model the relevant electronic states from Q to QH2 that may play a role in the activation of proton pump. We find that conformational changes in the hydrogen-bonded Q-binding modes regulate the rate of eT from the terminal N2 iron-sulfur center. Our combined data reveal how the dynamics of complex I-bound Q modulates the rate of terminal electron transfer, and how conserved residues in the Q-chamber contribute to the overall PCET process.