Biological electron transfer Marcus equation

The theoretical description of biological electron transfer has grown out of the pioneering work of Marcus on inorganic reactions in solution. The electron transfer process can be viewed as a nomadiative relaxation process from an initial state with the electron donor (D) reduced and the acceptor (A) oxidized to a final state with the donor oxidized and the acceptor reduced, according to equation (10). 

Blue copper proteins are involved in electron transfer (ET) reactions in organisms ranging from bacteria to humans. In order to understand the contribution of the electronic structure to the ET function of these sites, it is useful to examine the three primary terms that contribute to the rate of ET, as described by the semi-classical Marcus equation (1) see also Long-range Electron Transfer in Biology). 

The semiclassical Marcus equation can be applied to electron transfer between spatially fixed and oriented redox centers (26). Values obtained by employing this theoretical framework are in good agreement for both wild type and single-site mutants of Pae azurin (15), thus supporting the applicability of this analysis of the LRET process. The mechanism of intramolecular electron transfer through matrices of biological macromolecules, mainly proteins, has attracted considerable current interest (25). Moreover, the question of whether... 

It is possible to describe the antiferromagnetic term in Equation (5) in the same conceptual basis as that for Marcus electron-transfer theory " and the Hush model for intervalence transitions.Bertrand considered the case of electron transfer between biological molecules coupled by an exchange interaction. This is represented schematically by two metal sites separated by a bridging medium L (Scheme 1). 

Another great success of TM was the prediction of new pattern of reactivity for very exothermic electron transfers (the existence of an inverted region, to be discussed later in Section 16.5). The prediction of such pattern of reactivity against the scientific consensus at the time reveals how those simple ideas of Marcus, based on his quadratic equation, grasped one of the essential features of physical reality in this field, one which has important implications for fundamental biological processes such as photosynthesis. 

---