The effect of the base triplets adjacent to an X•CG triplet [X = T, 5-methylcytosine (C), or their LNA and ENA counterparts] in a triplex DNA was examined through the UV-melting experiments. Whereas the triplex containing a T•CG triplet, sandwiched by T•AT triplets, was stable, the replacement of T•AT with C•GC at the 5ʹ-adjacent site significantly destabilized the stability. When one or both of the adjacent T•AT triplets were replaced with C•GC, the triplexes containing a C•CG triplet were generally more stable than those containing a T•CG triplet. Further increases in the thermal stability of the triplexes were observed by LNA and ENA modifications. These results suggested that a C•CG triplet rather than a T•CG triplet would be suitable for triplex formation when C•GC triplets existed at its adjacent site.


中文翻译：

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三重态DNA中与T•CG或5-MethylC•CG三重态相邻的碱基三重态的作用

通过紫外熔融实验检查了三重DNA中邻近X•CG三重峰[X = T，5-甲基胞嘧啶（C ）或它们的LNA和ENA对应物]的三胞胎的作用。含有T•CG三联体的三联体被T•AT三联体夹在中间是稳定的，而在5′相邻位点用C •GC取代T•AT的稳定性大大破坏了稳定性。当一个或两个相邻的T•AT三联体替换为C •GC时，含有C •CG三联体的三联体通常比含有T•CG三联体的三联体更稳定。通过LNA和ENA修饰，可以观察到三链体的热稳定性进一步提高。这些结果表明，一个ç当C •GC三联体存在于其相邻位点时，•CG三联体而不是T•CG三联体更适合于三联体的形成。