This award in the Inorganic, Bioinorganic and Organometallic Chemistry program supports research by Professor Bruce E. Bowler at the University of Denver to investigate fundamental aspects of gating and dynamics of electron transfer (ET) reactions in proteins. The model system to be investigated is based on the alkaline conformer of cytochrome c (Cytc). The rate of ET gating and the rate of the conformational change involved in gating will be measured independently and the thermodynamics of the conformational change will be assessed. Rates of gated ET in the iso-1-Cytc model system, will be determined by (1) varying the position of the histidine ligand in the surface loop unfolded by the alkaline conformer as a means of extending the range of gating rates available, (2) introducing substitutions for Phe 82 to fine-tune the 100 ms gating rate of the His 73-heme alkaline conformer and (3) replacing Pro 76 with Gly to simplify ET gating kinetics. The effect on electronic coupling by mutations at positions 52 and 67, which modulate the dynamics of the surface loop running from positions 40 to 57 in Cytc will also be probed. Substrates for photoinducible gated ET in the iso-1-Cytc model system will be developed.
These studies will provide fundamental insight into the factors that affect electron transfer in proteins and practical strategies for protein-based molecular electronics devices. The research provides undergraduate and graduate students with independent forefront research projects. Consequently, the students trained in this project will be primed to move toward the emerging field of molecular electronics.
