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Kotulic Bunta, J.*; Laaksonen, A.*; Pinak, M.; Nemoto, Toshiyuki*
Computational Biology and Chemistry, 30(2), p.112 - 119, 2006/04
Times Cited Count：3 Percentile：22.11(Biology)Due to their lethal consequences, single and double strand breaks are among the most important and dangerous DNA lesions. This work defines and analyzes a DNA with single strand break as a template study for future complex analyses of biologically serious double strand break damage and its enzymatic repair mechanisms. Besides a non-damaged DNA serving as a reference system, system with open valences of the atoms at the strand break ends as well as a system with filled valences was simulated. As for the results, the system with open valences is partly disrupted, and the system with filled valences is stabilized by forming new hydrogen bonds between two strand endings.
Watanabe, Ritsuko; Nikjoo, H.*
International Journal of Radiation Biology, 78(11), p.953 - 966, 2002/11
Times Cited Count：38 Percentile：89.62(Biology)Incorporation of halogenated pyrimidines, iodo- and bromo-deoxyuridines (HP), into DNA is known to sensitize cells to radiation. The aim of this study is to estimate the enhancement of DNA strand break induced by low LET radiation in the presence of HP and examine source, complexity and clustering properties of damage that could provide correlation between DNA damage and lethality. Monte Carlo track structure methods were used to model the induction of strand breakage by X-ray photons. As a result, the increase of strand breaks due to Br/IdU incorporation could be explained by the mechanism of uracilyl radical production originated from e-aq and direct hits on bases. The significant contribution of electron migration along DNA within limited distance is shown. It is also shown that the incorporation of Br/IdU causes a spectral shift towards greater complexity of clustered DNA damage. Further, it has been supported that DSB is responsible for radiation-induced cell killing.
