My research concerns the understanding of the rates and mechanism of electron transfer in biological systems. Model synthetic peptides derivatized with different donors and acceptors, as well as modified electron transfer proteins, where an acceptor or donor is covalently attached to the protein, are being studied. A combination of experiment and theory on rigid and constrained donor-acceptor complexes bridged by polypeptides with different secondary structure is helping us understand the dependence of rate on distances in these polypeptide complexes. Electronic structure calculation for a series of similar donor-acceptor peptides with different secondary structures is providing new ideas and challenges for understanding the effect of peptide secondary structures on electron transfer rates. Projects currently under investigation in my group include intramolecular electron transfer across constrained synthetic polypeptides and modified electron transfer proteins, designed to test the above theories. Other projects in the lab include using the information from the above studies to specifically immobilize proteins on self-assembled monolayers on gold electrodes. These oriented proteins on electrodes will be used to study electron transfer reactions in protein-protein complexes.