Terrissol M
Centre de Physique Atomique, Université Paul Sabatier, Toulouse, France.
Int J Radiat Biol. 1994 Nov;66(5):447-51. doi: 10.1080/09553009414551441.
Studies of early physical interactions of ionizing radiation in biological medium have evolved from water cylinders or spheres to structured volumes representing nucleosomal DNA, based on spatial co-ordinates for each individual atom. Regarding the physico-chemical and chemical stages, the models of DNA have evolved from inactive geometrical objects to active participation of DNA in the reactions with the radical species. In this paper data are presented on the modelling of the interaction of low energy electrons with nucleosomal DNA. The nucleosome core unit has been modelled as a 146-bp helical DNA, containing > 9000 atoms, wound around the core unit. The yields of strand breaks for low energy electrons has been obtained by placing the nucleosome target in a liquid water environment and introducing a number of assumptions for the induction of strand breaks. The calculated results for the induction of ssb and dsb by 125I decays agree with experimental data, confirming the plausibility of this nucleosome model as well as the characterization of the interaction of ionizing radiation in terms of the energy deposition and the assumptions made for the strand breaks.
对生物介质中电离辐射早期物理相互作用的研究已从水缸或球体发展到基于每个原子的空间坐标来表示核小体DNA的结构化体积。关于物理化学和化学阶段，DNA模型已从无活性的几何物体发展到DNA在与自由基物种的反应中积极参与。本文展示了关于低能电子与核小体DNA相互作用建模的数据。核小体核心单元被建模为一个146碱基对的螺旋DNA，包含9000多个原子，缠绕在核心单元周围。通过将核小体靶标置于液态水环境中并引入一些关于诱导链断裂的假设，获得了低能电子诱导链断裂的产率。125I衰变诱导单链断裂（ssb）和双链断裂（dsb）的计算结果与实验数据一致，证实了这种核小体模型的合理性以及就能量沉积和链断裂所作假设而言电离辐射相互作用的特征。
