Efficient Charge Transport via DNA G-Quadruplexes

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• 作者：Arun K. Thazhathveetil ; Michelle A. Harris ; Ryan M. YoungMichael R. Wasielewski ; Frederick D. Lewis
• 刊名：Journal of the American Chemical Society
• 出版年：2017
• 出版时间：February 8, 2017
• 年：2017
• 卷：139
• 期：5
• 页码：1730-1733
• 全文大小：358K
• ISSN：1520-5126

文摘

The dynamics and efficiency of photoinduced charge transport has been investigated in DNA capped hairpins possessing a stilbenedicarboxamide (Sa) hole donor and stilbenediether (Sd) hole acceptor separated by DNA G-quadruplex structures possessing 2-to-4 tetrads by means of femtosecond and nanosecond transient absorption spectroscopy with global analysis. The results for the quadruplex structures are compared with those for the corresponding duplex structures having G-C base pairs in place of the G-tetrads. Following photoinduced charge separation to form a contact radical ion pair, hole transport to form the Sa^–•/Sd^+• charge-separated state is slower but more efficient for the quadruplex vs duplex structures. Thus, the G-quadruplex serves as an effective conduit for positive charge rather than as a hole trap when inserted into a duplex, as previously postulated.