Assembly of supramolecular DNA complexes containing both G-quadruplexes and i-motifs by enhancing the G-repeat-bearing capacity of i-motifs.
Assembly of supramolecular DNA complexes containing both G-quadruplexes and i-motifs by enhancing the G-repeat-bearing capacity of i-motifs.
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通过增强i-基序的G-重复承载能力组装含有G-四链体和i-基序的超分子DNA复合物
DOI：
10.1093/nar/gkw1049
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发表时间：
2017-01-09
影响因子：
14.9
通讯作者：
Guo X
中科院分区：
文献类型：
--
作者：
Cao Y;Gao S;Yan Y;Bruist MF;Wang B;Guo X
证明了含有i基序和G四链体（G4）的超分子复合物的单步组装。这可以实现，因为四链i基序的形成似乎很少受到某些末端残基的影响：五胞嘧啶四聚体i基序可以携带十个碱基的侧翼残基。然而，当在胞嘧啶重复序列的3′或5′末端添加不同长度的鸟嘌呤重复序列时，事情变得复杂。在此，设计了一系列寡聚体d（XGiXC 5X）和d（XC 5XGiX）（X = A、T或无; i < 5）以研究G-重复对四聚体i-基序形成的影响。我们的数据表明，四分子的i-基序结构可以容忍特定的侧翼G-重复。这些寡核苷酸的组装是多态性的，但可以通过溶液pH和抗衡离子种类来控制。重要的是，我们发现序列d（TG 1AC 5）可以大量形成四聚体i基序。这导致了两种寡核苷酸d（TG 4AC 7）和d（TGBrGGBrGAC 7）的设计，其在某些条件下自组装以形成四链体超分子。d（TG 4AC 7）在酸性条件下在K+存在下形成超分子，其主要是V形或环状，含有平行的G4和反平行的i-基序。d（TGBrGGBrGAC 7）在Na+存在下在酸性条件下形成长的线性四链体线，其由反平行的G4和i-基序组成。
The single-step assembly of supramolecular complexes containing both i-motifs and G-quadruplexes (G4s) is demonstrated. This can be achieved because the formation of four-stranded i-motifs appears to be little affected by certain terminal residues: a five-cytosine tetrameric i-motif can bear ten-base flanking residues. However, things become complex when different lengths of guanine-repeats are added at the 3′ or 5′ ends of the cytosine-repeats. Here, a series of oligomers d(XGiXC5X) and d(XC5XGiX) (X = A, T or none; i < 5) are designed to study the impact of G-repeats on the formation of tetrameric i-motifs. Our data demonstrate that tetramolecular i-motif structure can tolerate specific flanking G-repeats. Assemblies of these oligonucleotides are polymorphic, but may be controlled by solution pH and counter ion species. Importantly, we find that the sequences d(TGiAC5) can form the tetrameric i-motif in large quantities. This leads to the design of two oligonucleotides d(TG4AC7) and d(TGBrGGBrGAC7) that self-assemble to form quadruplex supramolecules under certain conditions. d(TG4AC7) forms supramolecules under acidic conditions in the presence of K+ that are mainly V-shaped or ring-like containing parallel G4s and antiparallel i-motifs. d(TGBrGGBrGAC7) forms long linear quadruplex wires under acidic conditions in the presence of Na+ that consist of both antiparallel G4s and i-motifs.