Electronic transport in DNA - the disorder perspective

We are investigating the electronic properties of DNA by looking at a tight-binding model and four DNA sequences. The charge transfer is studied in terms of localisation lengths as a function of Fermi energy and backbone disorder, the latter accounting for different environments. We have performed calculations on poly(dG)-poly(dC), telomeric DNA, random-ATGC DNA, X-DNA and find that random-ATGC and X-DNA have localization lengths allowing for electron motion among a few dozen base pairs only, whereas for telomeric and poly(dG)-poly(dC) DNA they are much larger. Enhancement of localisation lengths is observed at particular energies for an increasing binary backbone disorder