4-amino-1H-benzo[g]quinazoline-2-one:: a fluorescent analog of cytosine to probe protonation sites in triplex forming oligonucleotides
4-amino-1H-benzo[g]quinazoline-2-one:: a fluorescent analog of cytosine to probe protonation sites in triplex forming oligonucleotides
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DOI：
10.1093/nar/28.15.2977
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发表时间：
2000-08-01
影响因子：
14.9
通讯作者：
Moreau, S
中科院分区：
文献类型：
--
作者：
Godde, F;Toulmé, JJ;Moreau, S
我们合成了一种新的胞嘧啶荧光类似物4-氨基-1H-苯并[g]喹唑啉-2-酮，它是一种对pH敏感的探针。合成了该杂环的2 ′-O-Me核苷衍生物，其荧光发射中心位于456 nm，具有四个主要的激发峰（250、300、320和370 nm）和在pH 7.1下Phi = 0.62的荧光量子产率。当pH从7.1降低到2.1时，荧光发射最大值从456移动到492 nm。pK（a）（4）与胞嘧啶的pK（4.17）接近。当引入到三聚体形成寡核苷酸中时，这种新的核苷可以用来揭示三链结构中三聚体的质子化状态，通过荧光发射的显著猝灭来检测复合物的形成（类似于88%）和喹唑啉环的N-3质子化通过发射最大值从485 nm移动到465 nm，使用这种探针，我们明确地表明，嘧啶基序的三倍体形成不需要所有4-氨基-2-酮嘧啶环的质子化。
We developed a new fluorescent analog of cytosine, the 4-amino-1H-benzo[g]quinazoline-2-one, which constitute a probe sensitive to pH, The 2'-O-Me ribonucleoside derivative of this heterocycle was synthesized and exhibited a fluorescence emission centered at 456 nm, characterized by four major excitation maxima (250, 300, 320 and 370 nm) and a fluorescence quantum yield of Phi = 0.62 at pH 7.1. The fluorescence emission maximum shifted from 456 to 492 nm when pH was decreased from 7.1 to 2.1. The pK(a) (4) was close to that of cytosine (4.17). When introduced in tripler forming oligonucleotides this new nucleoside can be used to reveal the protonation state of triplets in triple-stranded structures, Complex formation was detected by a significant quenching of fluorescence emission (similar to 88%) and the N-3 protonation of the quinazoline ring by a shift of the emission maximum from 485 to 465 nm, Using this probe we unambiguously showed that tripler formation of the pyrimidine motif does not require the protonation of all 4-amino-2-one pyrimidine rings.