Sequence effects on the charge transfer in DNA

COMP 188

Alexander Balaeff, abalaeff@duke.edu, Shahar Keinan, shahar@duke.edu, Ravindra Venkatramani, ravindra.venkatramani@duke.edu, and David N. Beratan, david.beratan@duke.edu. Department of Chemistry, Duke University, Durham, NC 27708
The effect of DNA sequence on charge transfer (CT) properties is studied for the DNA sequences GTnG (Giese et al., 2001) and GAnG. In singly oxidized DNA, the terminal Gs serve as a hole donor and acceptor separated by a bridge of n=1-5 AT base pairs. The energy and localization of the hole are calculated for ensembles of DNA structures obtained for each sequence by molecular dynamics. The hole delocalization between a G and its neighboring A is found to be significant in the GAnG sequences, resulting in the formation of GA "superdonors/superacceptors". Consequently, the hole is less likely to be localized solely on a G or on the bridge than in the GTnG sequences. We therefore predict that the transition between the superexchange and hopping CT regimes occurs at a longer bridge length in the GAnG sequence than at n=3 measured by Giese et al. for the GTnG sequence.

 

Poster Session
6:00 PM-8:00 PM, Tuesday, August 18, 2009 Walter E. Washington Convention Center -- Ballroom A, Poster

Division of Computers in Chemistry

The 238th ACS National Meeting, Washington, DC, August 16-20, 2009