Zhu Zhiyuan, Peng Mengna, Zhang Jingwen, Tan Lifeng
College of Chemistry, Xiangtan University, Xiangtan 411105, PR China.
Key Lab of Environment-friendly Chemistry and Application in Ministry of Education, Xiangtan University, Xiangtan 411105, PR China.
J Inorg Biochem. 2017 Apr;169:44-49. doi: 10.1016/j.jinorgbio.2017.01.004. Epub 2017 Jan 4.
Triple-helical RNA are of interest because of possible biological roles as well as the potential therapeutic uses of these structures, while the stability of triplexes is usually weaker than that of the Watson-Crick base pairing duplex strand due to the electrostatic repulsion between three polyanionic strands. Therefore, how to increase the stability of the specific sequences of triplexes are of importance. In this paper the binding of a Ru(II) complex, [Ru(bpy)(PIP)] (bpy=2.2'-bipyridine, PIP=2-phenyl-1H-imidazo[4,5-f]- [1,10]-phenanthroline), with poly(U)·poly(A)*poly(U) triplex has been investigated by spectrophotometry, spectrofluorometry, viscosimetry and circular dichroism. The results suggest that [Ru(bpy)(PIP)] as a metallointercalator can stabilize poly(U)·poly(A)*poly(U) triplex (where · denotes the Watson-Crick base pairing and * denotes the Hoogsteen base pairing),while it stabilizes third-strand with no obvious effect on the duplex of poly(U)·poly(A), reflecting the binding of this complex with the triplex is favored by the Hoogsteen paired poly(U) third strand to a great extent.
三链RNA因其可能的生物学作用以及这些结构的潜在治疗用途而备受关注，然而由于三条聚阴离子链之间的静电排斥作用，三链体的稳定性通常比沃森-克里克碱基配对双链体弱。因此，如何提高三链体特定序列的稳定性至关重要。本文通过分光光度法、荧光光谱法、粘度测定法和圆二色性研究了钌（II）配合物[Ru(bpy)(PIP)]（bpy = 2,2'-联吡啶，PIP = 2-苯基-1H-咪唑并[4,5-f][1,10]菲咯啉）与聚（U）·聚（A）*聚（U）三链体的结合。结果表明，[Ru(bpy)(PIP)]作为一种金属嵌入剂可以稳定聚（U）·聚（A）*聚（U）三链体（其中·表示沃森-克里克碱基配对，*表示 hoogsteen 碱基配对），同时它稳定第三链而对聚（U）·聚（A）双链体没有明显影响，这反映出该配合物与三链体的结合在很大程度上受 hoogsteen 配对的聚（U）第三链的青睐。
