On the mechanism of anion desorption from DNA induced by low energy electrons
- Group in the Radiation Sciences, Department of Nuclear Medicine and Radiobiology, Faculty of Medicine, Universite de Sherbrooke, Sherbrooke, Quebec J1H 5N4 (Canada)
Our knowledge of the mechanisms of radiation damage to DNA induced by secondary electrons is still very limited, mainly due to the large sizes of the system involved and the complexity of the interactions. To reduce the problem to its simplest form, we investigated specific electron interactions with one of the most simple model system of DNA, an oligonucleotide tetrameter compound of the four bases. We report anion desorption yields from a thin solid film of the oligonucleotide GCAT induced by the impact of 3-15 eV electrons. All observed anions (H{sup -}, O{sup -}, OH{sup -}, CN{sup -}, and OCN{sup -}) are produced by dissociative electron attachment to the molecule, which results in desorption peaks between 6 and 12 eV. Above 14 eV nonresonant dipolar dissociation dominates the desorption yields. By comparing the shapes and relative intensities of the anion yield functions from GCAT physisorbed on a tantalum substrate with those obtained from isolated DNA basic subunits (i.e., bases, deoxyribose, and phosphate groups) from either the gas phase or condensed phase experiments, it is possible to obtain more details on the mechanisms involved in low energy electron damage to DNA, particularly on those producing single strand breaks.
- OSTI ID:
- 20864317
- Journal Information:
- Journal of Chemical Physics, Vol. 125, Issue 14; Other Information: DOI: 10.1063/1.2338320; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
Similar Records
Electron stimulated desorption of anionic fragments from films of pure and electron-irradiated thiophene
Fragmentation dynamics of condensed phase thymine by low-energy (10-200 eV) heavy-ion impact