Persistence of structure over fluctuations in biological electron-transfer reactions.

In the soft-wet environment of biomolecular electron transfer, it is possible that structural fluctuations could wash out medium-specific electronic effects on electron tunneling rates. We show that beyond a transition distance (2-3 A in water and 6-7 A in proteins), fluctuation contributions to the mean-squared donor-to-acceptor tunneling matrix element are likely to dominate over the average matrix element. Even though fluctuations dominate the tunneling mechanism at larger distances, we find that the protein fold is "remembered" by the electronic coupling, and structure remains a key determinant of electron transfer kinetics.

[1]  I. Plante,et al.  SUPEREXCHANGE COUPLING AND ELECTRON TRANSFER IN HOMOGENEOUS THREE-DIMENSIONAL SYSTEMS : THE CONTINUOUS-MEDIUM APPROXIMATION , 1995 .

[2]  M. Ratner,et al.  Molecular Wires: Extended Coupling and Disorder Effects , 1996 .

[3]  A. Vela,et al.  Extended Hueckel parameters from density functional theory , 1988 .

[4]  Harry B Gray,et al.  Electron tunneling through proteins , 2003, Quarterly Reviews of Biophysics.

[5]  A. Stuchebrukhov.  Long-distance electron tunneling in proteins , 2003 .

[6]  David N Beratan,et al.  Protein dynamics and electron transfer: electronic decoherence and non-Condon effects. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[7]  J. Jortner,et al.  Effects of Configurational Fluctuation on Electronic Coupling for Charge Transfer Dynamics , 2003 .

[8]  Ravindra Venkatramani,et al.  PNA versus DNA: effects of structural fluctuations on electronic structure and hole-transport mechanisms. , 2008, Journal of the American Chemical Society.

[9]  Shigenori Tanaka,et al.  Modern methods for theoretical physical chemistry of biopolymers , 2006 .

[10]  David N. Beratan,et al.  The Nature of Aqueous Tunneling Pathways Between Electron-Transfer Proteins , 2005, Science.

[11]  H. Gray,et al.  Tryptophan-Accelerated Electron Flow Through Proteins , 2008, Science.

[12]  A. Warshel,et al.  Dynamics of biochemical and biophysical reactions: insight from computer simulations , 2001, Quarterly Reviews of Biophysics.

[13]  V. Pande,et al.  ELECTRON TRANSPORT IN DISORDERED POLYMERIC AND BIOLOGICAL SYSTEMS , 1997 .

[14]  Ilya A. Balabin,et al.  Dynamically controlled protein tunneling paths in photosynthetic reaction centers. , 2000, Science.

[15]  S. Skourtis,et al.  Comparative study of perturbative methods for computing electron transfer tunneling matrix elements with a nonorthogonal basis set. , 2006, The Journal of chemical physics.

[16]  R. Marcus,et al.  Electron transfers in chemistry and biology , 1985 .

[17]  José N. Onuchic,et al.  Connection between Simple Models and Quantum Chemical Models for Electron-Transfer Tunneling Matrix Element Calculations: A Dyson's Equations-Based Approach , 1996 .

[18]  David N Beratan,et al.  Coupling Coherence Distinguishes Structure Sensitivity in Protein Electron Transfer , 2007, Science.

[19]  John Taylor,et al.  Statistical Techniques for Data Analysis , 1990 .

[20]  A. Troisi,et al.  A rate constant expression for charge transfer through fluctuating bridges , 2003 .

[21]  Keith Yates,et al.  Huckel Molecular Orbital Theory , 1978 .