Probing Charge Transportin Oxidatively Damaged DNASequences under the Influence of Structural Fluctuations.

We present a detailed study of the charge transport characteristicsof double-stranded DNA oligomers including the oxidative damage 7,8-dihydro-8-oxoguanine(8-oxoG). The problem is treated by a hybrid methodology combiningclassical molecular dynamics simulations and semiempirical electronicstructure calculations to formulate a coarse-grained charge transportmodel. The influence of solvent- and DNA-mediated structural fluctuationsis encoded in the obtained time series of the electronic charge transferparameters. Within the Landauer approach to charge transport, we performa detailed analysis of the conductance and current time series obtainedby sampling the electronic structure along the molecular dynamicstrajectory, and find that the inclusion of 8-oxoG damages into theDNA sequence can induce a change in the electrical response of thesystem. However, solvent-induced fluctuations tend to mask the effect,so that a detection of such sequence modifications via electricaltransport measurements in a liquid environment seems to be difficultto achieve. [ABSTRACT FROM AUTHOR]