Regensburg 2004 – wissenschaftliches Programm

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AKB: Biologische Physik

AKB 50: Poster Session "Biological Physics"

AKB 50.52: Poster

Freitag, 12. März 2004, 10:30–13:00, B

Electronic Transport in DNA — •Daphne Klotsa, Rudolf A. Römer, and Matthew S. Turner — Department of Physics, University of Warwick, CV4 7AL, Coventry, United Kingdom

Based on a theoretical model proposed by Cuniberti et al. [1] we are focusing on electron localisation along the Deoxyribose Nucleic Acid (DNA) double helix, using a tight-binding Hamiltonian. The possibility that this organic super molecule might facilitate electron transfer, along the overlapping π-orbitals [2], as a means of signalling other biomolecules, has led us to perform calculations varying the DNA sequences. We have performed simulations on random sequence, λ- and telomeric DNA. For the first two the resulting localisation lengths as functions of energy and disorder show similar behaviour whereas the latter — specific sequence DNA — gives significantly larger localisation lengths. In all cases an energy bandgap, indicating semiconducting behaviour, has been observed. Counter intuitively, for random absorption of Sodium (Na) atoms onto the backbone, preliminary results have shown localisation lengths to increase with increasing disorder. A “moving window" technique will be used in order to assess whether particular shorter fragments of a sequence behave differently, whose contribution would inevitably be smoothed out when the whole sequence is considered. Finally, we are looking at another theoretical way of modelling DNA’s complex structure and properties, the “ladder model" — an extension of the aforementioned model.

[1] G. Cuniberti, et al., Phys. Rev. B 65, 241314 (2002)

[2] P. J. de Pablo, et al. Phys. Rev. Letters 85, 4992 (2000)