THYMINE LESIONS PRODUCED BY IONIZING-RADIATION IN DOUBLE-STRANDED DNA
THYMINE LESIONS PRODUCED BY IONIZING-RADIATION IN DOUBLE-STRANDED DNA
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DOI：
10.1021/bi00336a032
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发表时间：
1985-01-01
期刊：
影响因子：
2.9
通讯作者：
LINDAHL, T
中科院分区：
文献类型：
--
作者：
BREIMER, LH;LINDAHL, T
催化由环饱和、断裂或环收缩损伤的胸腺嘧啶残基从双链DNA中释放的DNA糖基化酶已被用于表征γ中的这种碱基衍生物。辐射DNA色谱分析表明，在中性溶液中照射DNA产生环饱和形式的顺式胸腺嘧啶乙二醇，反式胸腺嘧啶乙二醇，和一个单羟基二氢胸腺嘧啶，可能是6-羟基-5，6-二氢胸腺嘧啶。后一种化合物仅在低氧条件下照射后观察到。环收缩的胸腺嘧啶衍生物5-羟基-5-甲基乙内酰脲也形成，并且它是DNA在O2下照射后的主要损伤。环断裂产物，如甲基酒石酸脲，只产生少量。来自γ-DNA的分离和分析照射的人细胞也显示出环饱和胸腺嘧啶衍生物的形成，但在这种情况下没有发现5-羟基-5-甲基乙内酰脲。
A DNA glycosylase which catalyzes the release of thymine residues damaged by ring saturation, fragmentation, or ring contraction from double-stranded DNA has been used to characterize such base derivatives in .gamma.-irradiated DNA. It is shown by chromatographic analysis that irradiation of DNA in neutral solution generates the ring-saturated forms cis-thymine glycol, trans-thymine glycol, and a monohydroxydihydrothymine, probably 6-hydroxy-5,6-dihydrothymine. The latter compound is only observed after irradiation under hypoxic conditions. The ring-contracted thymine derivative 5-hydroxy-5-methylhydantoin is also formed, and it is the major lesion after irradiation of DNA under O2. Ring-fragmented products such as methyltartronylurea were only generated in small quantities. Isolation and analysis of the DNA from .gamma.-irradiated human cells also revealed the formation of ring-saturated thymine derivatives, but 5-hydroxy-5-methylhydantoin was not found in this case.