RESUMO
In a biological electron transfer reaction problem we have found distinct electron probability current representations of macromolecular currents, amino acid and interamino acid currents, atomic and interatomic currents. We present a general interatomic current approach to obtain the electron probability current from donor to acceptor sites, and vice versa. Symmetric (or antisymmetric) renormalizable interatomic currents provide exact (or approximate) effective tunneling matrix element between donor and acceptor states. The electron probability currents allow us to investigate stationary tunneling pathways through protein bridge medium, from molecular to subatomic resolution at any level of electronic description of the biological structure. Analytical comparison among interatomic pathway models is presented and we found equivalent interatomic current representations with distinct dependence on the tunneling energy from the weak to strong coupling between protein bridge and the donoracceptor sites.
Assuntos
Elétrons , Modelos Biológicos , Proteínas/química , Transporte de Elétrons , ProbabilidadeRESUMO
We develop nonorthogonal projectors, called Löwdin projectors, to construct an effective donor-acceptor system composed of localized donor (D) and acceptor (A) states of a long-distance electron transfer problem. When these states have a nonvanishing overlap with the bridge states these projectors are non-Hermitian and there are various possible effective two-level systems that can be built. We show how these can be constructed directly from the Schrödinger or Dyson equation projected onto the D-A subspace of the Hilbert space and explore these equations to determine the connection between Hamiltonian and Green function partitioning. We illustrate the use of these effective two-level systems in estimating the electron transfer rate in the context of a simple electron transfer model.