SEQUENCE SPECIFICITY IN PHOTOREACTION OF VARIOUS PSORALEN DERIVATIVES WITH DNA - ROLE IN BIOLOGICAL-ACTIVITY
SEQUENCE SPECIFICITY IN PHOTOREACTION OF VARIOUS PSORALEN DERIVATIVES WITH DNA - ROLE IN BIOLOGICAL-ACTIVITY
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DOI：
10.1021/bi00408a052
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发表时间：
1988-04-19
期刊：
影响因子：
2.9
通讯作者：
SAGE, E
中科院分区：
文献类型：
--
作者：
BOYER, V;MOUSTACCHI, E;SAGE, E
用DNA测序方法研究了不同的卟啉衍生物与DNA光反应的序列特异性。与T4 DNA聚合酶相关的3“-5”核酸外切酶活性用作探针，以在具有确定序列的DNA片段上定位peptides“光加成（单加合物加双加合物）。这种方法已经使我们能够证明对8-甲氧基吡喃烯与DNA光结合的强序列背景效应[Sage，E.，和Moustacchi，E.（1987）Biochemistry 26，3307-3314]。所研究的青霉烯包括双官能衍生物[8-甲氧基青霉烯、5-甲氧基青霉烯和4“-（羟甲基）-4，5”，8-三甲基青霉烯]和单官能衍生物（当归素、3-carbethoxypropylene和三种吡啶并青霉烯）。建立了所有衍生物的两个DNA片段的大肠杆菌的lacI基因的光化学结合的地图。这些图谱证明了呋喃香豆素与DNA的光反应中的以下一般定性规则：GC环境中的胸腺嘧啶残基是冷的，相邻的胸腺嘧啶是更好的靶点，5“-TpA位点相对于5”-ApT是强烈优选的，并且交替的（AT）n序列是光加成的热点。根据衍生物的化学结构及其对DNA的亲和力，检测到结合光谱中的一些微小差异。一个最有趣的例子是3-carbethoxypropylene，它特异性地与（AT）n位点反应。我们的观察使我们定义两种类型的靶位点：“强位点”，这是所有peptide衍生物的优先目标，和“弱位点”，这是targetss只为衍生物具有高亲和力的DNA。DNA损伤的频率在前一个部位要高得多。每个衍生物的特定的光化学结合进行了讨论，在构象方面和相关的研究呋喃香豆素诱导的修复和诱变。
The sequence specificity in the photoreaction of various psoralen derivatives with DNA is investigated by using DNA sequencing methodology. The 3''- 5'' exonuclease activity associated with T4 DNA polymerase serves as a probe to map the psoralens'' photoaddition (monoadducts plus biadducts) on DNA fragments of defined sequence. This approach has already allowed us to demonstrate a strong sequence context effect on the 8-methoxypsoralen photobinding to DNA [Sage, E., and Moustacchi, E. (1987) Biochemistry 26, 3307-3314]. The psoralens studied include bifunctional derivatives [8-methoxypsoralen, 5-methoxypsoralen, and 4''-(hydroxymethyl)-4,5'',8-trimethylypsoralen] and monofunctional derivatives (angelicin, 3-carbethoxypsoralen, and three pyridopsoralens). Maps of photochemical binding on two DNA fragments of the lacI gene of Escherichia coli are established for all the derivatives. These maps demonstrate the following general qualitative rules in the photoreaction of the furocoumarins with DNA: thymine residues in a GC environment are cold, adjacent thymines are better targets, 5''-TpA sites are strongly preferred versus 5''-ApT, and alternating (AT)n sequences are hot spots for photoaddition. Depending on the chemical structure of the derivatives and on their affinity for DNA, some minor differences in the binding spectrum are detected. A most interesting example is 3-carbethoxypsoralen, which specifically reacts with (AT)n sites. Our observations lead us to define two types of target sites: the "strong sites", which are preferential targets for all psoralen derivatives, and the "weak sites", which are targetss only for derivatives having a high affinity for DNA. The frequency of DNA lesions is much higher in the former sites. The specific photochemical binding of each derivative is discussed in conformational terms and related to the repair and mutagenesis induced by the studied furocoumarins.