Affiliation: Institucio Catalana de Recerca i Estudis Avancats, 08010 Barcelona, Spain; Institute of Computational Chemistry, University of Girona, 17071 Girona, Spain.
Fundamental biochemical processes such as respiration and photosynthesis rely on electron transfer (ET) between cofactors containing transition metal atoms. Donor-acceptor electronic coupling VDA is a key parameter that controls the ET rate. Accurate estimation of this parameter is challenging. In the paper, we consider different methods used to calculate the coupling matrix element for ET between transition-metal centers in proteins and discuss their advantages and limitations.