We propose a nonperturbative Green’s function approach for analyzing the effects of conformation on electron transfer matrix elements in proteins. This approach allows the analysis (at all levels of detail) of the contributions of different protein structural elements to the electronic coupling between donor and acceptor. It also describes propagation and interference, effects semianalytically. We define electronic contact maps and electronic propagation maps which can be used to interpret the effect of the protein’s conformation on the total donor-acceptor coupling.