Electron transfer between globular proteins. Dependence of the rate of transfer on distance

Based on the assumption that electron transfer between globular proteins occurs by a collective excitation of polaron type, the dependence of the rate of this process on the distance between the donor and acceptor centers with regard to their detailed electron structure was calculated. The electron structure of the heme was calculated by the quantum-chemical MNDO-PM3 method. The results were compared with experimental data on interprotein and intraglobular electron transfer. It is shown that, in the framework of this model, the electron transfer is not exponential and does not require a particular transfer pathway since the whole protein macromolecule is involved in the formation of the electron excited state.