标题： 并行的G- duplex和C- duplex DNA，具有AgI介导的碱基对的不间断骨架 显示英文标题

标题： Parallel G-duplex and C-duplex DNA with Uninterrupted Spines of AgI-Mediated Base Pairs

摘要： 核碱基之间的氢键产生多样的DNA结构模体，包括标准双螺旋、鸟嘌呤（G）四链体和胞嘧啶（C）i-结构。 将金属介导的碱基对引入核酸结构中可以引入新的功能性和增强的稳定性。 在这里，我们使用质谱（MS）、离子迁移谱（IMS）和荧光共振能量转移（FRET）证明，当天然DNA序列与银阳离子在水溶液中混合时，会形成由最多20个G-Ag(I)-G连续碱基对组成的平行链结构。 FRET表明，由含有20个连续C-Ag(I)-C碱基对的聚胞嘧啶链形成的双螺旋也是平行的。 银介导的G-双螺旋优先于G-四链体形成，Ag+将G-四链体转化为银配对双螺旋的能力可能为操控这些生物相关的结构提供了一条新途径。 IMS表明，G-双螺旋比B-DNA更线性和更刚性。 使用密度泛函理论（DFT）计算提出了与IMS实验相容的结构。 这种低成本、无缺陷且可溶的基于DNA的纳米线为设计新型金属介导的DNA纳米技术开辟了新方向。 显示英文摘要

摘要： Hydrogen bonding between nucleobases produces diverse DNA structural motifs, including canonical duplexes, guanine (G) quadruplexes and cytosine (C) i-motifs. Incorporating metal-mediated base pairs into nucleic acid structures can introduce new functionalities and enhanced stabilities. Here we demonstrate, using mass spectrometry (MS), ion mobility spectrometry (IMS) and fluorescence resonance energy transfer (FRET), that parallel-stranded structures consisting of up to 20 G-Ag(I)-G contiguous base pairs are formed when natural DNA sequences are mixed with silver cations in aqueous solution. FRET indicates that duplexes formed by poly(cytosine) strands with 20 contiguous C-Ag(I)-C base pairs are also parallel. Silver-mediated G-duplexes form preferentially over G-quadruplexes, and the ability of Ag+ to convert G-quadruplexes into silver-paired duplexes may provide a new route to manipulating these biologically relevant structures. IMS indicates that G-duplexes are linear and more rigid than B-DNA. DFT calculations were used to propose structures compatible with the IMS experiments. Such inexpensive, defect-free and soluble DNA-based nanowires open new directions in the design of novel metal-mediated DNA nanotechnology.