Department of Chemistry, Duke University, Durham, North Carolina 27708, United States.
Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.
Biochemistry. 2021 May 4;60(17):1368-1378. doi: 10.1021/acs.biochem.1c00072. Epub 2021 Apr 19.
The flow of charge through molecules is central to the function of supramolecular machines, and charge transport in nucleic acids is implicated in molecular signaling and DNA repair. We examine the transport of electrons through nucleic acids to understand the interplay of resonant and nonresonant charge carrier transport mechanisms. This study reports STM break junction measurements of peptide nucleic acids (PNAs) with a G-block structure and contrasts the findings with previous results for DNA duplexes. The conductance of G-block PNA duplexes is much higher than that of the corresponding DNA duplexes of the same sequence; however, they do not display the strong even-odd dependence conductance oscillations found in G-block DNA. Theoretical analysis finds that the conductance oscillation magnitude in PNA is suppressed because of the increased level of electronic coupling interaction between G-blocks in PNA and the stronger PNA-electrode interaction compared to that in DNA duplexes. The strong interactions in the G-block PNA duplexes produce molecular conductances as high as 3% , where is the quantum of conductance, for 5 nm duplexes.
电荷在分子中的流动是超分子机器功能的核心，而核酸中的电荷传输则与分子信号转导和 DNA 修复有关。我们研究了电子通过核酸的传输，以了解共振和非共振电荷载流子输运机制的相互作用。本研究报告了具有 G 块结构的肽核酸 (PNA) 的 STM 断键测量结果，并将这些结果与以前的 DNA 双链体结果进行了对比。G 块 PNA 双链体的电导比具有相同序列的相应 DNA 双链体高得多；然而，它们并没有显示出在 G 块 DNA 中发现的强奇偶电导振荡依赖性。理论分析发现，由于 PNA 中 G 块之间的电子耦合相互作用以及与 DNA 双链体相比更强的 PNA-电极相互作用，PNA 中的电导振荡幅度被抑制。在 G 块 PNA 双链体中，强相互作用产生了高达 3%的分子电导，其中 是电导的量子，对于 5nm 的双链体。
