Benabou Sanae, Garavís Miguel, Lyonnais Sébastien, Eritja Ramon, González Carlos, Gargallo Raimundo
Department of Analytical Chemistry, University of Barcelona, Diagonal 645, E-08028 Barcelona, Spain.
Institute of Physical Chemistry "Rocasolano", CSIC, Serrano 119, E-28006 Madrid, Spain.
Phys Chem Chem Phys. 2016 Mar 21;18(11):7997-8004. doi: 10.1039/c5cp07428b.
The nature and the length of loops connecting cytosine tracts in i-motif structures may affect their stability. In this work, the influence of the nature of the nucleobases located in two of the loops of an intramolecular i-motif is studied using spectroscopy, separation techniques, and multivariate data analysis. The insertion of bases other than thymine induces an additional acid-base equilibrium with pKa ∼ 4.5. The presence of two guanine bases in the loops, placed opposite to each other, decreases the thermal stability of the structure. In contrast, thymine and cytosine bases in these positions stabilize the structure.
在i-基序结构中，连接胞嘧啶片段的环的性质和长度可能会影响其稳定性。在这项工作中，利用光谱学、分离技术和多变量数据分析，研究了位于分子内i-基序两个环中的核碱基性质的影响。除胸腺嘧啶以外的碱基插入会诱导出一个pKa约为4.5的额外酸碱平衡。环中两个彼此相对的鸟嘌呤碱基的存在会降低结构的热稳定性。相比之下，这些位置的胸腺嘧啶和胞嘧啶碱基则会使结构稳定。
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