Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University , Evanston, Illinois 60208-3113, United States.
J Am Chem Soc. 2017 Feb 8;139(5):1730-1733. doi: 10.1021/jacs.6b10265. Epub 2017 Jan 27.
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.
通过飞秒和纳秒瞬态吸收光谱学的全局分析，研究了具有发夹结构的 DNA 中的光诱导电荷输运的动力学和效率，该 DNA 具有二苯乙烯二酰胺（Sa）空穴供体和二苯乙烯二醚（Sd）空穴受体，由具有 2 到 4 个四联体的 DNA G-四链体结构隔开。将四链体结构的结果与具有 G-C 碱基对代替 G-四联体的相应双链体结构的结果进行了比较。形成接触自由基离子对后，进行光诱导电荷分离，形成 Sa/Sd 电荷分离态。与双链体结构相比，四链体结构的空穴传输形成 Sa/Sd 电荷分离态虽然较慢，但效率更高。因此，当 G-四链体插入双链体时，它充当正电荷的有效通道，而不是空穴陷阱，这与之前的假设相反。
