Thermal and Photoinduced Long Distance Electron Transfer in Proteins and in Model Systems

All biological energy (and, thus, all fossil energy) is ultimately derived from a series of basic electron transfer reactions, starting with the primary charge separation in photosynthesis. The subsequent energy flow proceeds through a series of subsequent redox reactions, largely involving metallo-proteins in which the energy of reduction is coupled to proton transport and manufacture of ATP for biosyntheses. (Fig 1). 1Mitochondral electron transport chain. Despite the obvious importance of such redox reactions, until recently such reactions remained rather poorly characterised, and poorly understood. Within the past few years, however, rapid advances have occurred in several key areas, including: 1) electron transfer theory1-3 2) experiments on model reactions (eg: electron transfer at long, fixed distance),4-6 3) experimental techniques for monitoring rapid biological electron transfer,7-10 and 4) structural charaterization of the redox proteins themselves,11-15 including detailed models for the protein-protein complexes within which electron transfer occurs. As a result of these advances, rapid experimental