Stabilization of DNA Loop Structures by Large Cations
Stabilization of DNA Loop Structures by Large Cations
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DOI：
10.1021/acs.jpcb.9b06074
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发表时间：
2019-09-12
影响因子：
3.3
通讯作者：
Sugimoto, Naoki
中科院分区：
文献类型：
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作者：
Nakano, Shu-ichi;Ayusawa, Toshiya;Sugimoto, Naoki
由于碱基配对区域的空间排斥，大阳离子的 DNA 结合特性与金属离子不同。在本研究中，研究了不同大小阳离子存在下 DNA 二级结构（包括双链体、内环、凸出环、发夹环、悬空末端和 G 四链体）的热稳定性。大的阳离子，例如四丁基铵和四戊基铵离子，降低了完全匹配的双链体的稳定性，但增加了长环双链体的稳定性。阳离子还增加了长环 G-四链体的稳定性，并且低稳定性 G-四链体的稳定程度更大。对盐浓度依赖性的分析表明，大的阳离子与环核苷酸结合，从而抵消碱基配对的不稳定效应。当环核苷酸足够灵活以允许更大的阳离子更容易接近时，很可能发生结合。这些结果提供了对核酸与大阳离子分子相互作用的深入了解，并提出了一种在细胞内条件下稳定非规范 DNA 结构的潜在方法。
The DNA-binding properties of large cations differ from those of metal ions due to steric exclusion from base-paired regions. In this study, the thermal stability of DNA secondary structures, including duplexes, internal loops, bulge loops, hairpin loops, dangling ends, and G-quadruplexes, was investigated in the presence of cations of different sizes. Large cations, such as tetrabutylammonium and tetrapentylammonium ions, reduced the stability of fully matched duplexes but increased the stability of duplexes with a long loop. The cations also increased the stability of G-quadruplexes with a long loop, and the degree of stabilization was greater for low-stability G-quadruplexes. Analysis of the salt concentration dependence indicates that large cations bind to the loop nucleotides, leading to counteracting the destabilization effect on base pairing. It is likely that binding occurs when loop nucleotides are sufficiently flexible to allow for greater accessibility for large cations. These results provide insight into nucleic acid interactions with large cationic molecules and suggest a potential method for stabilizing noncanonical DNA structures under intracellular conditions.