G-quadruplex-binding ligand-induced DNA synapsis inside a DNA origami frame
G-quadruplex-binding ligand-induced DNA synapsis inside a DNA origami frame
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DNA折纸框架内的G-四链体结合配体诱导的DNA突触
DOI：
10.1039/c3ra45676e
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
K. Hidaka. P. L. T. Iran. M. P.
中科院分区：
文献类型：
--
作者：
A. Rajendran;M. Endo;K. Hidaka. P. L. T. Iran. M. P.
在基于dna的药物靶向方法中，g -四联体结合配体尤其令人感兴趣，因为在人类染色体端粒和几种原癌基因的启动子等区域中富含g的序列的丰度很高。许多四复体配体已经被报道，但它们在单分子水平上的功能还没有使用直接和实时的方法进行探索。在这里，我们报告了直接观察到双喹啉吡啶二甲酰胺与一端含有生物素的连接体诱导的四链g -四联体的形成。我们制作了一个DNA折纸框架，其中包含3-6个G-G错配的双链DNA在中间。在没有配体的情况下，通过高速原子力显微镜（HS-AFM）图像显示，感兴趣的双链dna没有相互作用。配体的存在诱导形成g -四联体结构，其特征为x形。将链霉亲和素添加到配体诱导的四重体中，使蛋白质定位在x形的中间，表明配体与四重体结合。通过HS-AFM捕获了配体诱导的四重构象形成及其通过去除配体而进行的反向构象转换的一系列实时图像。在我们的实时分析中记录了前所未有的中间状态。
Among the approaches for DNA-based drug targeting, G-quadruplex-binding ligands are of particular interest because of the high abundance of G-rich sequences in regions such as human chromosomal telomeres and promoters of several proto-oncogenes. A number of quadruplex-ligands have been reported, but their functions at single-molecule level have not been explored using direct and real-time methods. Here, we report on the direct observation of the formation of a four-stranded G-quadruplex induced by bisquinolinium pyridine dicarboxamide with a linker containing biotin at one end. We fabricated a DNA origami frame with incorporated duplex DNAs that contained 3–6 G–G mismatches in the middle. In the absence of ligand, the duplex DNAs of interest had no interaction, as visualized by their parallel-shape in high-speed atomic force microscopy (HS-AFM) images. Presence of ligand induced the formation of G-quadruplex structure, which was characterized by an X-shape. Addition of streptavidin to the ligand-induced quadruplex caused the protein to localize in the middle of the X-shape, indicating that the ligand is bound to the quadruplex. A sequence of real-time images of the ligand-induced formation of a quadruplex and its reverse conformational switching by removing the ligand was captured by HS-AFM. Unprecedented intermediate-like states were recorded in our real-time analysis.