Reaction centers electron transfer energetics

Wachtveitl, J., Huber, H., Feick, R., Rautter, J., Muh, F., and Lubitz, W. (1998) Electron transfer in bacterial reaction centers with an energetically raised primary acceptor ultrafast spectroscopy and endor/triple... 

The redox chlorins at the core of the various reaction centers form an obvious chain with separations of less than 6 A that ensure rates of 10 ps or less. The effect of this chain is to apparently make the photoinduced oxidant and reductant capable of residing briefly on any of the chlorins, subject principally to the free energy of that state and the energetic penalty of any uphill reverse electron transfer. When the free energy... 

Schmidt, S., Arlt, T., Hamm, P., Huber, H., Nagele, T, Wachtveitl, J., Meyer, M., Scheer, H., and Zinth, W., 1994, Energetics of the primary electron-transfer reaction revealed by ultrafast spectroscopy on modified bacterial reaction centers. Chem. Phys. Lett., 223 116fil20. 

Warshel, A., Chu, Z. T., and Parson, W. W., 1994, On the energetics of the primary electron-transfer process in bacterial reaction centers. J. Photochem. Photobiol., 82 123nl28. 

The theoretical treatment of electron transfer at metal electrodes has much in common with that for homogeneous electron transfer described in 12.2.3. The role of one of the reactants is taken by the electrode surface, which provides a rigid two-dimensional environment where reaction occurs. In some respects, electrode reactions represent a particularly simple class of electron-transfer reactions because only one redox center is required to be activated prior to electron transfer, and the proximity of the electrode surface often may yield only a weak, nonspecific influence on the activation energetics of the isolated reactant. As with homogeneous electron transfer, it is useful to consider that simple electrochemical reactions occur in two steps (1) formation from the bulk reactant of a precursor state with the reacting species located at a suitable site within the interphasial region where electron transfer can occur (2) thermal activation of the precursor species leading to electron transfer and subsequent deactivation to form the product successor state. 

Fig. 10. (A) and (B) Two models for the electron-transfer sequence in bacterial reaction centers. (C) Population densities of various intermediary states as a function of time calculated according to the model shown in (B). See text for discussion. Figure source (A) and (8) Holzapfel, Finkele, Kaiser, Oesterheldt, Scheer, Stilz and Zinth (1989) Observation of a bacteriochlorophyll anion radical during the primary charge separation in reaction center. Chem Phys Lett 160 5 (C) S Schmidt, T Arit, P Hamm, H Huber, T NSggle, J WachtveitI, M Meyer, H Scheer and W Zinth (1994) Energetics of the primary electron transfer reaction reveaied by ultrafast spectroscopy on modified bacterial reaction centers. Chem Phys Lett 223 118.

Problems Evaluating Energetics of Electron Transfer from Qa to Qb The Light-Exposed and Dark-Adapted Bacterial Reaction Center... 

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