DNA strand breaking by the hydroxyl radical is governed by the accessible surface areas of the hydrogen atoms of the DNA backbone
DNA strand breaking by the hydroxyl radical is governed by the accessible surface areas of the hydrogen atoms of the DNA backbone
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DOI：
10.1073/pnas.95.17.9738
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发表时间：
1998-08-18
影响因子：
11.1
通讯作者：
Tullius, TD
中科院分区：
文献类型：
--
作者：
Balasubramanian, B;Pogozelski, WK;Tullius, TD
尽管进行了广泛的研究，但关于双链DNA中哪一个脱氧核糖氢原子与羟基自由基反应最多的实验信息很少。为了研究这个问题，我们准备了一组双链DNA分子，其中氘在四个核苷酸之一的脱氧核糖的每个位置特异性地结合在一起。然后，我们测量了氘动力学同位素对羟基自由基切割DNA速率的影响。这些实验表明，羟基自由基与脱氧核糖的各种氢原子的反应顺序为5' H b> 4' H b> 3' H近似于2' H近似于1' H。这种反应顺序与脱氧核糖的氢暴露在溶剂中的顺序相似。因此，我们的工作揭示了羟基自由基与DNA反应的结构基础。这些结果也为电离辐射引起DNA损伤的机制提供了信息，并为DNA-蛋白质复合物的羟基自由基足迹解释和溶液中RNA和DNA结构的化学探针实验提供了原子水平的细节。
Despite extensive study, there is little experimental information available as to which of the deoxyribose hydrogen atoms of duplex DNA reacts most with the hydroxyl radical. To investigate this question, we prepared a set of double-stranded DNA molecules in which deuterium had been incorporated specifically at each position in the deoxyribose of one of the four nucleotides. We then measured deuterium kinetic isotope effects on the rate of cleavage of DNA by the hydroxyl radical. These experiments demonstrate that the hydroxyl radical reacts with the various hydrogen atoms of the deoxyribose in the order 5' H > 4' H > 3' H approximate to 2' H approximate to 1' H. This order of reactivity parallels the exposure to solvent of the deoxyribose hydrogens. Our work therefore reveals the structural basis of the reaction of the hydroxyl radical with DNA. These results also provide information on the mechanism of DNA damage caused by ionizing radiation as well as atomic-level detail for the interpretation of hydroxyl radical footprints of DNA-protein complexes and chemical probe experiments on the structure of RNA and DNA in solution.