Optimizing the Kinetics and Thermodynamics of DNA i-Motif Folding
Optimizing the Kinetics and Thermodynamics of DNA i-Motif Folding
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DOI：
10.1002/cbic.201300284
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发表时间：
2013-07-08
期刊：
影响因子：
3.2
通讯作者：
Schwalbe, Harald
中科院分区：
文献类型：
--
作者：
Lieblein, Anna Lena;Fuertig, Boris;Schwalbe, Harald
在微酸性条件下，单个富含胞苷的DNA链可以形成称为i基序的四链结构。i基序结构的稳定性是基于半质子化C-C+碱基对的插入。此外，这些结构的稳定性受pH、温度、盐浓度、每一富c延伸的胞苷数和序列长度的影响；它还取决于连接环区域的核苷酸。在这里，我们研究了环核苷酸对i-基序稳定性、结构和折叠动力学的影响，在五种环大小相同但环内腺苷和胸腺嘧啶残基不同的结构中。通过CD熔化测定了i基序结构的稳定性，并通过静态和时间分辨核磁共振实验研究了折叠结构和动力学。
Under slightly acidic conditions, single cytidine-rich DNA strands can form four-stranded structures called i-motifs. The stability of the i-motif structure is based on the intercalation of hemiprotonated C-C+ base pairs. In addition, the stability of these structures is influenced by pH, temperature, salt concentration, number of cytidines per C-rich stretch, and length of sequence; it also depends on the nucleotides in the connecting loop regions. Here, we investigated the influence of the loop nucleotides on i-motif stability, structure, and kinetics of folding, in five structures with the same loop-size but different adenosine and thymidine residues within the loop. The stabilities of the i-motif structures were determined by CD melting, and structure and kinetics of folding were studied by static and time-resolved NMR experiments.