David Beratan is supported by a grant from the Theoretical and Computational Chemistry Program to study response properties of biomolecules including electron transfer reactions and Raman spectroscopic probes of chirality. The goal of the proposed work is to develop a general new tool that will enable the theoretical exploration of biochemical structure-function and reactivity relations by exploiting the local nature of chemical interactions. An ab initio divide-and-conquer method is proposed, tailored to describe the electronic and vibronic response properties of macromolecules. The methods will be developed in such a way that they can be used to: 1) establish a link between 3D structure and electron transfer rates in proteins and DNA; 2) assist in relating molecular structure to chiroptical properties critical for drug discovery and protein structure determination, and 3) expand the structure-property interpretations of proteins available via Raman spectroscopy. The actual implementation of this strategy involves the use of an effective Hamiltonian, and Greens function theory to determine the relevant response function. A quantitative molecular-level description of biological function will arise from a detailed description of macromolecular electronic and vibronic structure. Yet, reliable electronic structure calculations are possible on systems of only modest size. Beratan's research program will enable the theoretical exploration of biochemical structure-function and reactivity relations at the molecular level for macromolecular systems of biological interest.
