First principles studies of electron tunneling in proteins.
A first principles study of electronic tunneling along the chain of seven Fe/S clusters in respiratory complex I, a key enzyme in the respiratory electron transport chain, is described. The broken-symmetry states of the Fe/S metal clusters calculated at both DFT and semi-empirical ZINDO levels were utilized to examine both the extremely weak electronic couplings between Fe/S clusters and the tunneling pathways, which provide a detailed atomistic-level description of the charge transfer process in the protein. One-electron tunneling approximation was found to hold within a reasonable accuracy, with only a moderate induced polarization of the core electrons. The method is demonstrated to be able to calculate accurately the coupling matrix elements as small as 10-4cm-1. A distinct signature of the wave properties of electrons is observed as quantum interferences of multiple tunneling pathways.
Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616.
Tomoyuki
T
Hayashi
Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616.
Alexei A
AA
Stuchebrukhov
Electron tunneling; cell respiration; electron transport chain; proteins