Long-range guanine damage in single-stranded DNA: Charge transport through a duplex bridge and in a single-stranded overhang
Long-range guanine damage in single-stranded DNA: Charge transport through a duplex bridge and in a single-stranded overhang
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DOI：
10.1021/ja992224r
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发表时间：
1999-12-01
影响因子：
15
通讯作者：
Schuster, GB
中科院分区：
文献类型：
--
作者：
Kan, YZ;Schuster, GB
制备了一系列蒽醌连接的DNA寡核苷酸，以检查双链体和单链区域中自由基阳离子的迁移和反应。在与含有AQ的链互补的链中存在较少的核苷酸，这产生了a。具有突出端的双链体。该互补链包含三个GG步骤，其用作自由基阳离子的陷阱。一个GG步骤位于双链体区域，第二个GG步骤位于双链体附近，第三个GG步骤位于单链突出端。在350 nm处的照射激发蒽醌并导致自由基阳离子注入双链体DNA区域。用哌啶或甲酰氨基嘧啶糖基化酶处理辐照样品，可导致链断裂，可通过聚丙烯酰胺凝胶电泳和放射自显影法检测。检查了各种寡核苷酸序列在三个GG步骤的反应性模式。这些研究证实，自由基阳离子反应的产物在单链和双链区不同，后者以7，8-二氢-8-氧代鸟嘌呤为主。结果表明，自由基阳离子可以从双链体区域迁移到单链上。自由基阳离子运输的单链悬垂提出进行鸟嘌呤通过直接接触GG错配对。
A series of anthraquinone-linked DNA oligonucleotides was prepared to examine the migration and reactions of radical cations in duplex and single-stranded regions. There are fewer nucleotides in the strand complementary to the AQ-containing Strand, which creates a. duplex with an overhang. This complementary strand contains three GG steps, which serve as traps for the radical cation. One GG step is in the duplex region, a second is adjacent to the duplex, and the third is in the single-strand overhang. Irradiation at 350 nm excites the anthraquinone and results in radical cation injection into the duplex DNA region. Treatment of the irradiated sample with piperidine or with formamidopyrimidine glycosylase results in strand cleavage that is detected by polyacrylamide gel electrophoresis and autoradiography. The pattern of reactivity at the three GG steps was examined for various oligonucleotide sequences. These studies confirm that the products of radical cation reaction differ in single-strand and duplex regions with 7,8-dihydro-8-oxo-guanine predominating in the latter. The results show that the radical cation can migrate from the duplex region onto the single strand. Radical cation transport in the single-strand overhang is proposed to proceed from guanine to guanine by means of direct contact in GG mispairs.