Bulge-like Asymmetric Heterodye Clustering in DNA Duplex Results in Efficient Quenching of Background Emission Based on the Maximized Excitonic Interaction
Bulge-like Asymmetric Heterodye Clustering in DNA Duplex Results in Efficient Quenching of Background Emission Based on the Maximized Excitonic Interaction
复制标题
DNA 双链体中的凸出状不对称异源聚类导致基于最大化激子相互作用的背景发射的有效猝灭
DOI：
10.1002/chem.201201365
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
H. Asanuma
中科院分区：
文献类型：
--
作者：
T. Fujii;Y. Hara;T. Osawa;H. Kashida;X. G. Liang;Y. Yoshida;H. Asanuma
制备了具有单个荧光团（Cy 3）和多个猝灭剂（4′-甲硫基偶氮苯-4-羧酸酯、甲基红和4′-二甲基氨基-2-硝基偶氮苯-4-羧酸酯）的不对称染料簇。染料和1 - 5个猝灭剂通过D-苏氨醇与DNA双链体的相对链连接。NMR分析表明，具有单个荧光团和两个猝灭剂的簇形成了三明治样结构（反平行H-聚集体）。所有的杂原子团簇的熔融温度几乎是相同的，虽然结构畸变应该变得更大，作为淬灭剂的数量增加。单个荧光团和两个猝灭剂的不对称杂簇显示出更大的激子相互作用（即，与单一Cy 3和单一猝灭剂相比，Cy 3具有更高的荧光强度（例如，Cy 3的减色性）。由于染料之间的激子耦合较大，1：2杂原子团簇比1：1团簇更有效地抑制背景发射。然而，由于激子与两种猝灭剂的耦合饱和，更多的猝灭剂并没有提高猝灭效率。最后，将这种不对称的1：2异源簇引入分子信标（MB;也称为茎内MB）的茎区，靶向L 6 BCR-ABL融合基因中的融合位点。利用这种MB设计，由于有效抑制了由最大化激子相互作用产生的背景发射，信号/背景比高达68。
Asymmetric dye clusters with a single fluorophore (Cy3) and multiple quenchers (4′‐methylthioazobenzene‐4‐carboxylate, methyl red, and 4′‐dimethylamino‐2‐nitroazobenzene‐4‐carboxylate) were prepared. The dye and one‐to‐five quenchers were tethered throughD‐threoninol to opposite strands of a DNA duplex. NMR analysis revealed that the clusters with a single fluorophore and two quenchers formed a sandwich‐like structure (antiparallel H‐aggregates). The melting temperatures of all the heteroclusters were almost the same, although structural distortion should become larger, as the number of quenchers increased. An asymmetric heterocluster of a single fluorophore and two quenchers showed larger excitonic interaction (i.e., hypochromicity of Cy3), than did a single Cy3 and a single quencher. Due to the larger exciton coupling between the dyes, the 1:2 heterocluster suppressed the background emission more efficiently than the 1:1 cluster. However, more quenchers did not enhance quenching efficiency due to the saturation of exciton coupling with two quenchers. Finally, this asymmetric 1:2 heterocluster was introduced into the stem region of a molecular beacon (MB; also known as an in‐stem MB) targeting the fusion site in the L6BCR‐ABLfusion gene. With this MB design, the signal/background ratio was as high as 68 due to efficient suppression of background emission resulting from the maximized excitonic interaction.