Quadruplex formation as a molecular switch to turn on intrinsically fluorescent nucleotide analogs.
Quadruplex formation as a molecular switch to turn on intrinsically fluorescent nucleotide analogs.
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DOI：
10.1093/nar/gks975
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发表时间：
2013-01-07
影响因子：
14.9
通讯作者：
Kankia B
中科院分区：
文献类型：
--
作者：
Johnson J;Okyere R;Joseph A;Musier-Forsyth K;Kankia B
四重体参与基因表达的调控，是染色体末端端粒的一部分。此外，它们还可用于治疗和生物技术应用，包括核酸诊断。在K+离子存在下，两个15-mer序列d(GGTTGGTGTGGTTGG)（凝血酶结合适体）和d(GGGTGGGTGGGTGGG) （G3T）分别折叠成反平行和平行四联体。在本研究中，我们测量了一个或多个结合在四重体形成序列环位置的2-氨基嘌呤或6-甲基异黄嘌呤碱基类似物的荧光强度，以建立溶液中DNA序列的检测方法。在四重体形成之前，荧光在所有情况下都被有效猝灭。值得注意的是，G3T四重构成物在所有三个位置上都发出与自由碱基相同的荧光。在凝血酶结合适体的情况下，发射强度取决于荧光核苷酸的位置。圆二色性研究表明，修饰不会改变整体二级结构，而热展开实验显示，荧光类似物显着破坏了四聚体的稳定性。总的来说，这些研究表明含有荧光核苷酸类似物的四联体是开发新型DNA检测方法的有用工具。
Quadruplexes are involved in the regulation of gene expression and are part of telomeres at the ends of chromosomes. In addition, they are useful in therapeutic and biotechnological applications, including nucleic acid diagnostics. In the presence of K+ ions, two 15-mer sequences d(GGTTGGTGTGGTTGG) (thrombin binding aptamer) and d(GGGTGGGTGGGTGGG) (G3T) fold into antiparallel and parallel quadruplexes, respectively. In the present study, we measured the fluorescence intensity of one or more 2-aminopurine or 6-methylisoxanthopterin base analogs incorporated at loop-positions of quadruplex forming sequences to develop a detection method for DNA sequences in solution. Before quadruplex formation, the fluorescence is efficiently quenched in all cases. Remarkably, G3T quadruplex formation results in emission of fluorescence equal to that of a free base in all three positions. In the case of thrombin binding aptamer, the emission intensity depends on the location of the fluorescent nucleotides. Circular dichroism studies demonstrate that the modifications do not change the overall secondary structure, whereas thermal unfolding experiments revealed that fluorescent analogs significantly destabilize the quadruplexes. Overall, these studies suggest that quadruplexes containing fluorescent nucleotide analogs are useful tools in the development of novel DNA detection methodologies.
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影响因子：
2.9
作者：
MARKY, LA;BRESLAUER, KJ
通讯作者：
BRESLAUER, KJ
影响因子：
15
作者：
Kankia, BI;Marky, LA
通讯作者：
Marky, LA
影响因子：
5.6
作者：
Matsugami, A;Ouhashi, K;Katahira, M
通讯作者：
Katahira, M
影响因子：
14.9
作者：
Martí AA;Jockusch S;Li Z;Ju J;Turro NJ
通讯作者：
Turro NJ
影响因子：
4.8
作者：
Jing, NJ;Hogan, ME
通讯作者：
Hogan, ME