A Nucleosome Model for the Simulation of DNA Strand Break Experiments
Using a set of Monte Carlo simulation models, track structures of 125I Auger electrons generated in liquid water are superimposed on a nucleosome DNA model able to precisely localize energy deposition events on sub-molecular units of the DNA strands. After scoring direct hits taking place during the physical phase (at about 10−15 s) the radiation chemistry of the whole system is simulated between 10−12 and 10−8 s, taking into account all reactions between water radio-chemical species, radicals, sub-molecular units of DNA (Ribose, Adenine, Thymine, Guanine and Cytosine), and scavengers like Tris or Formate ions.
The model’s possibility to distinguish between direct and indirect hits has been utilized to introduce different assumptions for strand break induction by both hit modes. The number of SSB and DSB as well as their local distribution will be given and compared with experimental and theoretical results from the literature.
KeywordsAuger Electron Strand Breakage Radiation Research Track Structure Physical Phase
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- 1.E. Pomplun. A New DNA Target Model for Track Structure Calculations and its First Application to 1251 Auger Electrons. Int. J. Radial. Biol. 59: 625–642 (1991).Google Scholar
- 2.M. Terrissol and E. Pomplun. Computer Simulation of DNA-incorporated 125I Auger Cascades and of the Associated Radiation Chemistry in Aqueous Solution. Radiation Protection Dosimetry 51: 171–181 (1994).Google Scholar
- 3.E. Pomplun. DNA Helix and Nucleosome Models in the Track Structure Analysis of Beta Particles and Auger Electrons from Incorporated H-3 and I-125, Radiation Research, Volume 1, J.D. Chapman, W.C. Dewey, G.F. Whitmore (eds.) Ninth International Congress of Radiation Research, 1991, Toronto.Google Scholar
- 5.E. Pomplun, M. Roch and M. Terrissol. Simulation of Strand Break Induction by DNA-incorporated 1251, Biophysical Aspects of Auger Processes, AAPM Symposium Series No. 8 (1992) 137 - 152, Eds. RW Howell, VR Narra, KSR Sastry, DV Rao.Google Scholar
- 6.M. Terrissol. Méthode de Simulation du Transport d’Electrons d’Energies Comprises entre 10 eV et 30 keV. Thesis, Université Paul Sabatier, n° 839, Toulouse (1978).Google Scholar
- 7.M. Terrissol and A. Beaudré. Simulation of Space and Time Evolution of Radiolytic Species Induced by Electrons in Water. Radiat. Prot. Dosim. 31: 171–175 (1990).Google Scholar
- 8.G.V. Buxton, C.L. Greenstock, W. P. Hetman and A. B. Ross. Critical Review of Rate Constants for Reactions of Hydrated Electrons, Hydrogen Atoms and Hydroxyl Radicals in Aqueous Solution. J. Phys. Chem. Ref Data, 17, No. 2, (1988).Google Scholar
- 10.L.E. Feinendegen, P. Henneberg and G. Tisljar-Lentulis. DNA Strand Breakage and Repair in Human Kidney Cells after Exposure to Incorporated 125I and 60Co 7-rays. Current Topics in Radiation Research Quarterly, 12: 436–452 (1977).Google Scholar
- 11.R.E. Krisch, F. Krasin and C.J. Sauri. DNA Breakage, Repair, and Lethality Accompanying 125í Decay in Microorganisms. Current Topics in Radiation Research Quarterly, 12: 355–368 (1977).Google Scholar