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BP: Fachverband Biologische Physik

BP 3: Computational Biophysics I

BP 3.2: Vortrag

Montag, 27. März 2023, 09:45–10:00, BAR 0106

Migration of oxygen in the human bc1 complex and the behavior of QH2 and Q cofactors inside it — •Katarina Kretschmer, Malena Kottke, and Ilia Solov'yov — Insitute of Physics, University of Oldenburg, Oldenburg, Germany

The dimeric bc1-complex embedded in the inner membrane of mitochondria is a relevant part of the respiratory chain in a mitochondrial cell of eukaryotes. Through different electron transfers that include oxidation and reduction reactions of the substrate molecules at the Qo- and Qi-site in this protein complex, it contributes to the metabolic system of the cell. Specifically, the complex facilitates proton transfers across the membrane to maintain an electrostatic potential, which is in turn used to drive ATP synthesis. This molecular machinery, however, is suspected to be a source of superoxide and is believed to be one of the factors in cellular aging.

Through molecular dynamics simulations, we have investigated the migration of molecular oxygen in the bc1-complex in order to identify possible reaction sites that could lead to superoxide formation. The investigation follows an earlier study of the bc1-complex from Rhodbacter capsulatus and reveals several important differences. Specifically, we investigate further into the behavior of the cofactors Ubiquinol (QH2) and Ubiquinone (Q) in both monomers in the bc1-complex and determine the oxygen diffusion pathways that could lead to the sites where O2 could be efficiently converted to superoxide, thereby disturbing the regular functioning of the bc1-complex.