Conformationally Gated Charge Transfer in DNA Three-Way Junctions
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- 作者：Yuqi Zhang ; Ryan M. Young ; Arun K. Thazhathveetil ; Arunoday P. N. Singh ; Chaoren Liu ; Yuri A. Berlin ; Ferdinand C. Grozema ; Frederick D. Lewis ; Mark A. Ratner ; Nicolas Renaud ; Khatcharin Siriwong ; Alexander A. Voityuk ; Michael R. Wasielewski ; David N. Beratan
- 刊名：The Journal of Physical Chemistry Letters
- 出版年：2015
- 出版时间：July 2, 2015
- 年：2015
- 卷：6
- 期：13
- 页码：2434-2438
- 全文大小：366K
- ISSN：1948-7185
文摘
Molecular structures that direct charge transport in two or three dimensions possess some of the essential functionality of electrical switches and gates. We use theory, modeling, and simulation to explore the conformational dynamics of DNA three-way junctions (TWJs) that may control the flow of charge through these structures. Molecular dynamics simulations and quantum calculations indicate that DNA TWJs undergo dynamic interconversion among 鈥渨ell stacked鈥?conformations on the time scale of nanoseconds, a feature that makes the junctions very different from linear DNA duplexes. The studies further indicate that this conformational gating would control charge flow through these TWJs, distinguishing them from conventional (larger size scale) gated devices. Simulations also find that structures with polyethylene glycol linking groups (鈥渆xtenders鈥? lock conformations that favor CT for 25 ns or more. The simulations explain the kinetics observed experimentally in TWJs and rationalize their transport properties compared with double-stranded DNA.