Crystal Structure of a Tetrameric DNA Fold-Back Quadruplex
Crystal Structure of a Tetrameric DNA Fold-Back Quadruplex
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DOI：
10.1021/jacs.8b10153
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发表时间：
2018-11-28
影响因子：
15
通讯作者：
Paukstelis, Paul J.
中科院分区：
文献类型：
--
作者：
Chu, Betty;Zhang, Daoning;Paukstelis, Paul J.
除了沃森克里克双链体之外，DNA还可以采用许多结构。然而，DNA结构多样性的界限以及这些结构如何调节生物过程才刚刚开始被理解。在这里，我们描述了1.05埃分辨率的DNA寡核苷酸的晶体结构，自缔合形成一个非G-四链体折叠回结构。不同于先前描述的折叠回四链体，两个折叠回二聚体通过非正则和沃森-克里克相互作用相互作用，形成一个四聚体组装。这些相互作用包括来自两个C-G-G碱基三联体的六碱基配对排列。组装依赖于二价阳离子，并且二聚体单元之间的界面产生阳离子驻留的空腔。这种结构为折叠四链体的形成提供了新的序列和结构背景，进一步突出了这种非典型DNA结构的潜在生物学重要性。这种结构也可以作为设计基于强二价阳离子依赖性的新型DNA纳米结构或阳离子传感器的基础。
DNA can adopt many structures beyond the Watson Crick duplex. However, the bounds of DNA structural diversity and how these structures might regulate biological processes is only beginning to be understood. Here, we describe the 1.05 angstrom resolution crystal structure of a DNA oligonucleotide that self-associates to form a non-G-quadruplex fold-back structure. Distinct from previously described fold-back quadruplexes, two-fold-back dimers interact through noncanonical and Watson-Crick interactions to form a tetrameric assembly. These interactions include a hexad base pairing arrangement from two C-G-G base triples. The assembly is dependent on divalent cations, and the interface between the dimeric units creates a cavity in which a cation resides. This structure provides new sequence and structural contexts for the formation of fold-back quadruplexes, further highlighting the potential biological importance of this type of noncanonical DNA structure. This structure may also serve as the basis for designing new types of DNA nanoarchitectures or cation sensors based on the strong divalent cation dependence.