Single-Molecule Manipulation of the Duplex Formation and Dissociation at the G-Quadruplex/i-Motif Site in the DNA Nanostructure

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• 作者：Masayuki Endo ; Xiwen Xing ; Xiang Zhou ; Tomoko Emura ; Kumi Hidaka ; Bodin Tuesuwan ; Hiroshi Sugiyama
• 刊名：ACS Nano
• 出版年：2015
• 出版时间：October 27, 2015
• 年：2015
• 卷：9
• 期：10
• 页码：9922-9929
• 全文大小：538K
• ISSN：1936-086X

文摘

We demonstrate the single-molecule operation and observation of the formation and resolution of double-stranded DNA (dsDNA) containing a G-quadruplex (GQ) forming and counterpart i-motif forming sequence in the DNA nanostructure. Sequential manipulation of DNA strands in the DNA frame was performed to prepare a topologically controlled GQ/i-motif dsDNA. Using strand displacement and the addition and removal of K⁺, the topologically controlled GQ/i-motif dsDNA in the DNA frame was obtained in high yield. The dsDNA was resolved into the single-stranded DNA, GQ, and i-motif by the addition of K⁺ and operation in acidic conditions. The dissociation of the dsDNA under the GQ and i-motif formation condition was monitored by high-speed atomic force microscopy. The results indicate that the dsDNA containing the GQ- and i-motif sequence is effectively dissolved when the duplex is helically loosened in the DNA nanoscaffold.