Time-resolved study of thymine dimer formation
Time-resolved study of thymine dimer formation
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DOI：
10.1021/ja050648h
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发表时间：
2005-04-27
影响因子：
15
通讯作者：
Markovitsi, D
中科院分区：
文献类型：
--
作者：
Marguet, S;Markovitsi, D
在室温下，用266 nm激光闪光光解研究了单链寡核苷酸(Dt)20中胸腺嘧啶二聚体的形成。结果表明，(6-4)加合物是通过反应中间体在4ms内形成的。环丁烷二聚体的形成速度快于200 ns。(6-4)的总量子产率为(3.7±0.3)×10-3，环丁烷二聚体的总量子产率为(2.8±0.2)×10-2。没有检测到三重态的吸收，表明齐聚反应(~lt；1.4×10~(-3))时系间交叉产率下降1个数量级，或者三重态与单元效率在200 ns以内反应生成环丁烷二聚体。
The formation of thymine dimers in the single-stranded oligonucleotide, (dT)20, is studied at room temperature by laser flash photolysis using 266 nm excitation. It is shown that the (6-4) adduct is formed within 4 ms via a reactive intermediate. The formation of cyclobutane dimers is faster than 200 ns. The overall quantum yield for the (6-4) formation is (3.7 ± 0.3) × 10-3, and that of the cyclobutane dimers is (2.8 ± 0.2) × 10-2. No triplet absorption is detected, showing that either the intersystem crossing yield decreases by 1 order of magnitude upon oligomerization (<1.4 × 10-3) or the triplet state reacts with unit efficiency in less than 200 ns to yield cyclobutane dimers.