单个人类端粒重复序列d(TTAGGG)对长链端粒DNA-d[AGGG(TTAGGG)6]结构影响的研究

本文使用超速离心沉降速度法、聚丙烯酰胺凝胶电泳和圆二色光谱和紫外吸收检测熔融实验研究了长序列端粒DNA-d[AGGG(TTAGGG)₆](G₆-DNA)的结构以及单个重复序列DNA-d(TTAGGG)(G₀₁-DNA)对G₆-DNA结构的影响. 结果表明G₆-DNA可以在水溶液中形成二聚体,并且G₀₁-DNA可以通过与G₆-DNA结合形成额外的G-四链体结构,从而改变单体与二聚体的平衡. 然而,G₀₁-DNA对序列为d[AGGG(TTAGGG)₃](G₃-DNA)的结构没有影响. 该研究为长序列单链端粒DNA的结构多样性提供了新的见解.     

Effect of a Single Repeat Sequence of the Human Telomere d(TTAGGG) on Structure of Single-Stranded Telomeric DNA d[AGGG(TTAGGG)\begin{document}$_6$\end{document}]

The structures of human telomeric DNA have received much attention due to its significant biological importance. Most studies have focused on G-quadruplex structure formed by short telomeric DNA sequence, but little is known about the structures of long single-stranded telomeric DNAs. Here, we investigated the structure of DNA with a long sequence of d[AGGG(TTAGGG)\begin{document}$_6$\end{document}] (G\begin{document}$_6$\end{document}-DNA) and the effect of a single repeat sequence d(TTAGGG) (G\begin{document}$_{01}$\end{document}-DNA) on the structure of G\begin{document}$_6$\end{document}-DNA using sedimentation velocity technique, polyacrylamide gel electrophoresis, circular dichroism spectroscopy, and UV melting experiments. The results suggest that the G\begin{document}$_6$\end{document}-DNA can form dimers in aqueous solutions and G\begin{document}$_{01}$\end{document}-DNA can form additional G-quadruplex structures by binding to G\begin{document}$_6$\end{document}-DNA. However, G\begin{document}$_{01}$\end{document}-DNA has no effect on the structure of DNA with a sequence of d[AGGG(TTAGGG)\begin{document}$_3$\end{document}] (G\begin{document}$_3$\end{document}-DNA). Our study provides new insights into the structure polymorphism of long human single-stranded telomeric DNA.