Different scenarios for inter-protein electron tunneling: The effect of water-mediated pathways

Abstract

Recent theoretical developments now allow for reliable calculation of tunneling matrix elements in unimolecular biological electron transfer reactions that have been tested experimentally. Most biological ET processes, however, are bimolecular, or involve large-scale protein domain motions. In this paper, initial advances in this direction by studying the inter-protein electron transfer between cytochrome c2 and the photosynthetic reaction center. Utilizing an approach that integrates molecular dynamics and the Pathways method, we have observed that the ensemble dominant tunneling pathways in this reaction go though the tyrosine 162 or are water mediated.