胸腺嘧啶二聚体形成的时间分辨研究。

Time-resolved study of thymine dimer formation.

作者信息

Marguet Sylvie, Markovitsi Dimitra

机构信息

Laboratoire Francis Perrin, CEA/DSM/DRECAM/SPAM-CNRS, URA 2453, CEA Saclay, 91191 Gif-sur-Yvette, France.

出版信息

J Am Chem Soc. 2005 Apr 27;127(16):5780-1. doi: 10.1021/ja050648h.

DOI:10.1021/ja050648h

PMID:15839663

Abstract

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) x 10-3, and that of the cyclobutane dimers is (2.8 +/- 0.2) x 10-2. No triplet absorption is detected, showing that either the intersystem crossing yield decreases by 1 order of magnitude upon oligomerization (<1.4 x 10-3) or the triplet state reacts with unit efficiency in less than 200 ns to yield cyclobutane dimers.

摘要

在室温下，使用266nm激发光通过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)加合物通过反应中间体在4ms内形成。环丁烷二聚体的形成速度快于200ns。(6-4)加合物形成的总量子产率为(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。未检测到三重态吸收，这表明要么在寡聚化时系间窜越产率降低了1个数量级(<1.4×10-3)，要么三重态以单位效率在不到200ns的时间内反应生成环丁烷二聚体。