Chemistry of High-Energy Content Reagents

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With this renewal award the Organic and Macromolecular Chemistry Program supports the work of Dr. Gary B. Schuster at Georgia Institute of Technology in Atlanta. The research aims to extend earlier work on electron conduction in DNA, with the idea of understanding the details of the conduction process. Oxidation of DNA, with removal of an electron as a first step, followed by electron migration to the initial radical cation to give a guanine (G) radical cation, and eventual DNA strand cleavage at a G site, is a major source of genetic damage, and can lead in some cases to cancer causing mutations or cell death.The proposed research will focus on testing various aspects of the phonon-assisted polaron-hopping mechanism of electron motion. In this model, the oxidation of a base in the DNA initiates a structural distortion as the chain contorts to delocalize the initial radical cation over adjacent base pairs. The delocalized radical cation is called a polaron. Polarons are thought to migrate along the DNA like a compression moves through a spring, as base pairs adjacent to the polaron join it and others leave as a consequence of thermal motion (phonons), while electrons hop from base to base. Trapping of the polaron by water leads to the chemical damage of the DNA. Students who participate in this research will learn a number of experimental techniques; the learning will be enhanced by collaborations with other scientists with special instrumentation and expertise.