Computational modelling of low-energy electron-induced DNA damage by early physical and chemical events
Computational modelling of low-energy electron-induced DNA damage by early physical and chemical events
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DOI：
10.1080/095530097143798
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发表时间：
1997-05-01
影响因子：
2.6
通讯作者：
Terrissol, M
中科院分区：
文献类型：
--
作者：
Nikjoo, H;ONeill, P;Terrissol, M
建模和计算的基础上产生的低能量电子（100 eV-4.5keV），可以与实验信息相比，初始DNA损伤的光谱辐射效应的机械解释和预测的第一步。相对产量的单和集群链断裂的复杂性和来源的损害，无论是通过直接的能量沉积或OH自由基的反应，并依赖于OH自由基的活化概率和所需的能量的量，以给出一个单链断裂（SSB）。数据显示，DNA中的大多数相互作用不会导致链断裂形式的损伤，并且当它们发生时，它们通常是简单的ssb。然而，对于双链断裂（dsb），高比例（约30%）是更复杂的形式，即使不考虑碱基损伤的额外复杂性。更大的贡献来自DNA中的直接相互作用，但OH自由基的反应大大增加了这一点，无论是在断裂总数方面，还是在增加簇内的复杂性方面。已经表明，来自单个电子径迹的DNA受损片段的长度往往很短，这表明随后的缺失长度（仅仅是由于邻近dsb之间的片段丢失）将很短，很少超过几十个碱基对。
Modelling and calculations are presented as a first step towards mechanistic interpretation and prediction of radiation effects based on the spectrum of initial DNA damage produced by low energy electrons (100eV-4.5keV) that can be compared with experimental information. Relative yields of single and clustered strand breaks are presented in terms of complexity and source of damage, either by direct energy deposition or by reaction of OH radicals, and dependence on the activation probability of OH radicals and the amount of energy required to give a single strand break (ssb). Data show that the majority of interactions in DNA do not lead to damage in the form of strand breaks and when they do occur, they are most frequently simple ssb. However, for double-strand breaks (dsb), a high proportion (similar to 30%) are of more complex forms, even without considering additional complexity from base damage. The greater contribution is from direct interactions in the DNA but reactions of OH radicals add substantially to this, both in terms of the total number of breaks and in increasing the complexity within a cluster. It has been shown that the lengths of damaged segments of DNA from individual electron tracks tend to be short, indicating that consequent deletion length (simply by loss of a fragment between nearby dsb) would be short, very seldom exceeding a few tens of base pairs.