Electron transfer between [4Fe–4S] clusters

Iron–sulfur clusters [4Fe–4S] are major components in biological electron transport (ET). Using the DFT/B3LYP method, we calculate electronic coupling for low- and high-potential ET between [4Fe–4S] clusters and explore its sensitivity to structural parameters of the system and external electric field. As an example, we consider a model of the bacterial respiratory complex I and estimate the role of neighboring amino acids in facilitating the ET process between the clusters. Our results suggest that the superexchange mechanism rather than hole hopping should be operative in ET between [4Fe–4S] redox centers.