Radioprobing of DNA: distribution of DNA breaks produced by decay of 125I incorporated into a triplex-forming oligonucleotide correlates with geometry of the triplex.
Radioprobing of DNA: distribution of DNA breaks produced by decay of 125I incorporated into a triplex-forming oligonucleotide correlates with geometry of the triplex.
复制标题
DNA 的放射性探测：掺入三链体形成寡核苷酸中的 125I 衰变产生的 DNA 断裂的分布与三链体的几何形状相关。
作者：
I. Panyutin;R. Neumann
在单核苷酸分辨率下，研究了由三链形成的DNA寡核苷酸携带的125I衰变在DNA双链的两条链上产生的断裂的分布。125I原子位于寡核苷酸的单个胞嘧啶残基的C5位置，该寡核苷酸被设计成与靶序列双链形成三螺旋。大多数断裂(90%)位于衰变部位周围的10BP以内。添加自由基清除剂DMSO对裂解产物的产量和分布影响不大。这些结果表明，这些断裂中的大多数是由辐射的直接作用产生的，而不是由可扩散的自由基介导的。嘌呤链的断裂频率是嘧啶链的两倍。断裂产量的这种不对称性与这种类型的三链的几何结构有关；第三链中胞嘧啶的C5更接近嘌呤链的糖-磷酸骨架。此外，对分子模型的研究表明，单个碱基的断裂产量与距离125I衰变点的距离有关。我们建议使用~(125)I衰变作为核酸和核蛋白复合体结构的探针。
The distribution of breaks produced in both strands of a DNA duplex by the decay of 125I carried by a triplex-forming DNA oligonucleotide was studied at single nucleotide resolution. The 125I atom was located in the C5 position of a single cytosine residue of an oligonucleotide designed to form a triple helix with the target sequence duplex. The majority of the breaks (90%) are located within 10 bp around the decay site. The addition of the free radical scavenger DMSO produces an insignificant effect on the yield and distribution of the breaks. These results suggest that the majority of these breaks are produced by the direct action of radiation and are not mediated by diffusible free radicals. The frequency of breaks in the purine strand was two times higher that in the pyrimidine strand. This asymmetry in the yield of breaks correlates with the geometry of this type of triplex; the C5 of the cytosine in the third strand is closer to the sugar-phosphate backbone of the purine strand. Moreover, study of molecular models shows that the yield of breaks at individual bases correlates with distance from the 125I decay site. We suggest the possible use of 125I decay as a probe for the structure of nucleic acids and nucleoprotein complexes.
影响因子：
56.9
作者：
MARTIN, RF;HASELTINE, WA
通讯作者：
HASELTINE, WA