Alkali-labile sites and post-irradiation effects in single-stranded DNA induced by H radicals.
Alkali-labile sites and post-irradiation effects in single-stranded DNA induced by H radicals.
复制标题
H 自由基诱导的单链 DNA 的碱不稳定位点和辐射后效应。
DOI：
10.1080/09553007814550151
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发表时间：
1978
期刊：
影响因子：
--
通讯作者：
H. Loman
中科院分区：
文献类型：
--
作者：
M. Lafleur;M. van Heuvel;J. Woldhuis;H. Loman
单链phiX 174 DNA在水溶液中已被照射在没有氧气的情况下，在只有H自由基与DNA反应的条件下。结果表明，H自由基反应导致断裂，这有助于约10%的失活。此外，形成两种类型的碱不稳定位点。一种是致命的，碱引起单链断裂，很可能与辐射后热损伤相同，对上述失活的贡献约为33%。另一种为非致死性损伤，部分为二氢嘧啶衍生物，碱可将其转化为致死性损伤。这是从用四氧化锇处理DNA的实验中得出的，四氧化锇将胸腺嘧啶氧化为5，6-二羟基-二氢胸腺嘧啶。用碱处理该DNA给出了与在辐照DNA中的非致死性碱不稳定位点所发现的相同的温度依赖性。发现二氢胸腺嘧啶和辐射嘧啶与碱的类似温度依赖性。
Single-stranded phiX174 DNA in aqueous solutions has been irradiated in the absence of oxygen, under conditions in which only H radicals react with the DNA. It was shown that H radical reactions result in breaks, which contribute approximately 10 per cent inactivation. Further, two types of alkali-labile sites are formed. One is lethal and gives rise to single-strand breaks by alkali and is most probably identical with post-irradiation heat damage and contributes about 33 per cent to the inactivation mentioned above. The other consists of non-lethal damage, partly dihydropyrimidine derivatives, and is converted to lethal damage by alkali. This follows from experiments in which the DNA was treated with osmium-tetroxide, which oxidizes thymine to 5,6-dihydroxy-dihydrothymine. Treatment with alkali of this DNA gives the same temperature dependence as found for the non-lethal alkali-labile sites in irradiated DNA. A similar temperature dependence is found for dihydrothymine and irradiated pyrimidines with alkali.