title: Charge Transfer at the Qo-Site of the Cytochrome bc1Complex Leads to Superoxide Production.
abstract: The cytochrome bc1complex is the third protein complex in the electron transport chain of mitochondria or photosynthetic bacteria, and it serves to create an electrochemical gradient across a cellular membrane, which is used to drive ATP synthesis. The purpose of this study is to investigate interactions involving an occasionally trapped oxygen molecule (O2) at the so-called Qosite of the bc1complex, which is one of the central active sites of the protein complex, where redox reactions are expected to occur. The investigation focuses on revealing the possibility of the oxygen molecule to influence the normal operation of the bc1complex and acquire an extra electron, thus becoming superoxide, a biologically toxic free radical. The process is modeled by applying quantum chemical calculations to previously performed classical molecular dynamics simulations. Investigations reveal several spontaneous charge transfer modes from amino acid residues and cofactors at the Qo-site to the trapped O2molecule.
authors.affiliation: Department of Physics, Chemistry and Pharmacy, University of Southern Denmark , Campusvej 55, DK-5230 Odense M, Denmark.
authors.forename: Adrian Bøgh
authors.initials: AB
authors.lastname: Salo
authors.affiliation: Department of Physics, Chemistry and Pharmacy, University of Southern Denmark , Campusvej 55, DK-5230 Odense M, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Husen
authors.affiliation: Department of Physics, Chemistry and Pharmacy, University of Southern Denmark , Campusvej 55, DK-5230 Odense M, Denmark.
authors.forename: Ilia A
authors.initials: IA
authors.lastname: Solov'yov
mesh_terms: D001665:Binding Sites; D020134:Catalytic Domain; D004579:Electron Transport; D014450:Electron Transport Complex III / Q000737:chemistry / Q000378:metabolism*; D056004:Molecular Dynamics Simulation; D010100:Oxygen / Q000378:metabolism*; D011485:Protein Binding; D016354:Rhodobacter capsulatus / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*; D013816:Thermodynamics
chemical_list: D013481:Superoxides; D014450:Electron Transport Complex III; D010100:Oxygen