title: Simulation of electron transfer between cytochrome C2 and the bacterial photosynthetic reaction center: Brownian dynamics analysis of the native proteins and double mutants.
abstract: Electron transfer is essential for bacterial photosynthesis which converts light energy into chemical energy. This paper theoretically studies the interprotein electron transfer from cytochrome c(2) of Rhodobacter capsulatus to the photosynthetic reaction center of Rhodobacter sphaeroides in native and mutated systems. Brownian dynamics is used with an exponential distance-dependent electron-transfer rate model to compute bimolecular rate constants, which are consistent with experimental data when reasonable prefactors and decay constants are used. Interestingly, switching of the reaction mechanism from the diffusion-controlled limit in the native proteins to the activation-controlled limit in one of the mutants (DK(L261)/KE(C99)) was found. We also predict that the second-order rate for the native reaction center/cytochrome c(2) system will decrease with increasing ionic strength, a characteristic of electrostatically controlled docking.
authors.affiliation: Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Jianping
authors.initials: J
authors.lastname: Lin
authors.forename: David N
authors.initials: DN
authors.lastname: Beratan
mesh_terms: D000465:Algorithms; D002627:Chemistry, Physical / Q000379:methods*; D003580:Cytochromes / Q000737:chemistry; D004058:Diffusion; D004583:Electrons; D007477:Ions; D008027:Light; D008956:Models, Chemical; D009154:Mutation; D016011:Normal Distribution; D045322:Photosynthetic Reaction Center Complex Proteins; D011506:Proteins / Q000737:chemistry*; D012242:Rhodobacter sphaeroides / Q000378:metabolism; D055672:Static Electricity; D013816:Thermodynamics
chemical_list: D003580:Cytochromes; D007477:Ions; D045322:Photosynthetic Reaction Center Complex Proteins; D011506:Proteins