Mapping of peroxyl radical induced damage on genomic DNA.
Mapping of peroxyl radical induced damage on genomic DNA.
复制标题
绘制过氧自由基诱导的基因组 DNA 损伤图谱。
DOI：
10.1021/bi9918994
复制
发表时间：
1999
期刊：
影响因子：
2.9
通讯作者：
Termini,J
中科院分区：
文献类型：
--
作者：
Rodriguez,H;Valentine,MR;Holmquist,GP;Akman,SA;Termini,J
We have examined the DNA damage produced by reaction of peroxyl radicals with human fibroblast DNA. DNA damage consisted of both strand breaks and base modifications. The extent of strand breaks and base modifications induced as a function of peroxyl radical concentration was determined by quantitation of fragment size distributions using denaturing glyoxal-agarose gel electrophoresis. Both strand breaks and base modifications increased in a log linear fashion with respect to peroxyl radical concentration. Oxidative base modifications were observed to occur to a greater extent than strand breaks at every concentration measured. The sequence-specific distribution of peroxyl radical induced base damage was mapped for 803 nucleotide positions using the method of ligation mediated PCR. A total of 87% of all guanine positions in the examined sequences was found to be significantly oxidized. The order of reactivity of DNA bases toward oxidation by peroxyl radicals was found to be G ≫ C > T. Adenine is essentially unreactive. The yield of oxidative base modifications at guanines and cytosines by peroxyl radicals depends on the exact specification of 5‘ and 3‘ flanking bases in a polarity dependent manner. Every guanine in the 5‘XGC3‘ motif was found to be oxidized, where X is any 5‘ neighbor. In contrast, 5‘ and 3‘ purine flanks drastically reduced the extent of peroxyl radicalGoxidation. The pattern of base modification and the influence of nearest neighbors differs substantially from that previously reported for hydrogen peroxide damage mediated by low valent transition metal ions for the identical DNA sequences.
