The loneliness of the electrons in the bc1 complex.
A stochastic approach based on Gillespie algorithm is particularly well adapted to describe the time course of the redox reactions that occur inside the respiratory chain complexes because they involve the motion of single electrons between individual unique redox centres of a given complex and not populations of electrons and redox centres as usually considered in ordinary differential equations. In this way we approach the molecular functioning of the bc(1) complex based on its known crystallographic structure and the rate constants of electron tunnelling derived from the Moser and Dutton phenomenological equation. The main features of our simulations are the dominant and robust emergence of a Q-cycle mechanism and the near absence of short-circuits in the normal functioning of the bc(1) complex. Thus, in our paper, the Mitchell Q-cycle no longer appears as an a priori hypothesis but arises out of the bc(1) complex structure and of the kinetic laws of redox reactions.
Université de Bordeaux 2, 146 rue Léo-Saignat, F 33076, Bordeaux-cedex, France.
Stéphane
S
Ransac
Nicolas
N
Parisey
Jean-Pierre
JP
Mazat
D001665:Binding Sites; D003198:Computer Simulation; D045304:Cytochromes c / Q000737:chemistry / Q000378:metabolism; D004579:Electron Transport; D014450:Electron Transport Complex III / Q000737:chemistry* / Q000378:metabolism*; D004583:Electrons; D007700:Kinetics; D008433:Mathematics; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011487:Protein Conformation; D013269:Stochastic Processes
D045304:Cytochromes c; D014450:Electron Transport Complex III