Unified Mechanism for the Generation of Isolated and Clustered DNA Damages by a Single Low Energy (5–10 eV) Electron

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• 作者：Yu Shao ; Yanfang Dong ; Darel Hunting ; Yi ZhengLéon Sanche
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：February 2, 2017
• 年：2017
• 卷：121
• 期：4
• 页码：2466-2472
• 全文大小：397K
• ISSN：1932-7455

文摘

Clustered DNA damages are the most detrimental modifications induced by ionizing radiation in cells and several mechanisms have been proposed for their formation. We report measurements of such damages induced by a single low energy electron via the formation of the two major core-excited resonances of DNA located at 4.6 and 9.6 eV. Cross-links and single and double strand breaks (SSBs and DSBs) are analyzed by gel electrophoresis. Treatment of irradiated samples with Esherichia coli base excision repair endonucleases reveals base damages (BDs). DSBs resulting from such treatments arise from clustered damages consisting of at least two BDs or one BD accompanied by a SSB. The total DNA damages induced by 4.6 and 9.6 eV electrons are 132 ± 32 and 201 ± 36 × 10^–15 electron^–1 molecule^–1, comprising 43% and 52% BDs, respectively. We propose a unifying mechanism to account for these clustered damages, DSBs, and single BDs, as well as all previously measured isolated lesions.