title: Microdosimetry of DNA conformations: relation between direct effect of (60)Co gamma rays and topology of DNA geometrical models in the calculation of A-, B- and Z-DNA radiation-induced damage yields.
abstract: In order to obtain the energy deposition pattern of ionizing radiation in the nanometric scale of genetic material and to investigate the different sensitivities of the DNA conformations, direct effects of (60)Co gamma rays on the three A, B and Z conformations of DNA have been studied. For this purpose, single-strand breaks (SSB), double-strand breaks (DSB), base damage (BD), hit probabilities and three microdosimetry quantities (imparted energy, mean chord length and lineal energy) in the mentioned DNA conformations have been calculated and compared by using GEometry ANd Tracking 4 (Geant4) toolkit. The results show that A-, B- and Z-DNA conformations have the highest yields of DSB (1.2 Gy(-1) Gbp(-1)), SSB (25.2 Gy(-1) Gbp(-1)) and BD (4.81 Gy(-1) Gbp(-1)), respectively. Based on the investigation of direct effects of radiation, it can be concluded that the DSB yield is largely correlated to the topological characteristics of DNA models, although the SSB yield is not. Moreover, according to the comparative results of the present study, a reliable candidate parameter for describing the relationship between DNA damage yields and geometry of DNA models in the theoretical radiation biology research studies would be the mean chord length (4 V/S) of the models.
authors.affiliation: Radiation Applications Research School, Nuclear Science and Technology Research Institute, P.O. Box: 11365-3486, Tehran, Iran.|Institute of Biochemistry and Biophysics (IBB), University of Tehran, P.O. Box: 13145-1384, Tehran, Iran.
authors.forename: Farid
authors.initials: F
authors.lastname: Semsarha
authors.affiliation: Radiation Applications Research School, Nuclear Science and Technology Research Institute, P.O. Box: 11365-3486, Tehran, Iran. graisali@aeoi.org.ir.
authors.forename: Gholamreza
authors.initials: G
authors.lastname: Raisali
authors.affiliation: Institute of Biochemistry and Biophysics (IBB), University of Tehran, P.O. Box: 13145-1384, Tehran, Iran.
authors.forename: Bahram
authors.initials: B
authors.lastname: Goliaei
authors.affiliation: Radiation Applications Research School, Nuclear Science and Technology Research Institute, P.O. Box: 11365-3486, Tehran, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Khalafi
mesh_terms: D003037:Cobalt Radioisotopes / Q000009:adverse effects*; D004249:DNA Damage; D059371:DNA, B-Form / Q000737:chemistry* / Q000235:genetics; D043542:DNA, Z-Form / Q000737:chemistry* / Q000235:genetics; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays / Q000009:adverse effects*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation / Q000528:radiation effects*; D011874:Radiometry
chemical_list: D003037:Cobalt Radioisotopes; D059371:DNA, B-Form; D043542:DNA, Z-Form
keywords: 60Co gamma rays; A-DNA; B-DNA; Direct effects; Geant4-DNA; Microdosimetry; Z-DNA