QUANTUM-MECHANICAL ELECTRON MIGRATION MODELS
Tunneling mechanism provides effective electron transport between donor-acceptor groups, which are placed at the distance of 10-15 Å. It does not require large-scale transport of whole molecules, though it is accompanied by change of equilibrium nuclear configuration of the system as the result of change of the charges of molecule states and the transition of the system to another potential energy surface. According to quantum concepts, a particle (electron, individual nuclei) has a certain probability of passing through a potential barrier, the energy of with is more than the energy of the particle itself. Such "filtering" through a barrier, or, tunneling, does not require thermal activation. There is probability to find the particle in various points of the space, surrounding it, including the region beyond the potential barrier. The tunneling mechanism provides an elementary act of electron transfer between donor-acceptor groups in proteins. For all that, the route of tunneling does not necessarily coincide with the shortest distance between the donor of the electron and its acceptor. The route of an electron can run along the electronic path through the core of protein chain between the links n1 and n2.