Communication: Microsecond dynamics of the protein and water affect electron transfer in a bacterial bc(1) complex.
Cross-membrane electron transport between cofactors localized in proteins of mitochondrial respiration and bacterial photosynthesis is the source of all biological energy. The statistics and dynamics of nuclear fluctuations in these protein/membrane/water heterogeneous systems are critical for their energetic efficiency. The results of 13 μs of atomistic molecular dynamics simulations of the membrane-bound bc1 bacterial complex are analyzed here. The reaction is affected by a broad spectrum of nuclear modes, with the slowest dynamics in the range of time-scales ∼0.1-1.6 μs contributing half of the reaction reorganization energy. Two reorganization energies are required to describe protein electron transfer due to dynamical arrest of protein conformations on the observation window. This mechanistic distinction allows significant lowering of activation barriers for reactions in proteins.
Department of Physics and Department of Chemistry and Biochemistry, Arizona State University, P.O. Box 871504, Tempe, Arizona 85287, USA.
Daniel R
DR
Martin
Department of Physics and Department of Chemistry and Biochemistry, Arizona State University, P.O. Box 871504, Tempe, Arizona 85287, USA.
Dmitry V
DV
Matyushov
D020134:Catalytic Domain; D004579:Electron Transport; D014450:Electron Transport Complex III / Q000737:chemistry / Q000378:metabolism*; D056004:Molecular Dynamics Simulation; D012242:Rhodobacter sphaeroides / Q000201:enzymology*; D013816:Thermodynamics; D014867:Water / Q000378:metabolism*
D014867:Water; D014450:Electron Transport Complex III