Direct Observation of Fast Electron Transfer Reactions in DNA Base Pairs via QM/MM Simulations

• Applicant: Dr. Thomas Steinbrecher
• Subject Area: Biological and Biomimetic Chemistry
• Term: from 2006 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 29077921

The goal of this work is to study fast intramolecular charge transfer reactions in radical cation or neutral DMA double strands by means of computer simulations. Contrary to previous works in the field, a single all- inclusive theoretical model will be employed to describe the DNA bases directly involved in the electron transfer reaction, the dynamics of the remaining DNA molecule and the surrounding solvating medium.By using a QM/MM methodology, in which only the base pairs directly involved in charge transfer are treated quantum mechanically, it is possible to study the evolution of the system on timescales from the sub-femtosecond to several nanoseconds length. This allows for the observation of, among others, two important occurences in DNA conductivity: the transfer of an electron between neighbouring adenine bases, responsible for long range charge transport in DNA damaging processes, as well as the impact of thermal dynamics on the band gap that is critical in ascertaining what type of conductor DNA is.Simulations of DNA molecules at different conditions will be performed so that a statistically significant number of charge transfer events are observed and the resulting reaction rates can be compared to experimental data and previous theoretical work.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor David A. Case