College of Chemistry, Xiangtan University, Xiangtan, 411105, People's Republic of China.
Academic Affairs Office, Xiangtan University, Xiangtan, 411105, People's Republic of China.
J Biol Inorg Chem. 2019 Aug;24(5):721-731. doi: 10.1007/s00775-019-01685-y. Epub 2019 Jul 16.
Two ruthenium(II) polypyridyl complexes containing different ancillary ligands, [Ru(bpy)(dppz-Br)] (Ru1; bpy = 2,2'-bipyridine dppz-Br = 7-Br-dipyrido[3,2-a,2',3'-c]-phenazine) and [Ru(dmb)(dppz-Br)] (Ru2; dmb = 4,4'-dimethyl-2,2'-bipyridine), have been synthesized and characterized. Binding properties of Ru1 and Ru2 with the RNA poly(U)•poly(A)*poly(U) triplex have been investigated by UV-Vis spectroscopy, fluorescence spectroscopy, viscosity measurements as well as circular dichroism and thermal denaturation. Spectrophotometric studies together with viscosity measurements suggest that both Ru1 and Ru2 bind with the triplex by intercalation mode, and the melting experiments demonstrate that the two complexes can effectively enhance the triplex stabilization. However, results indicate that Ru1 stabilizes the third-strand and Watson-Crick base-paired duplex of the triplex without obvious selectivity. In contrast, Ru2 prefers to bind with the third strand rather than the Watson-Crick base-paired duplex of the triplex to a some extent under the same conditions used in this study, thereby significantly stabilizing the third strand. The obtained results of this study suggest that slight differences in the ancillary ligands bpy and dmb should be the main factor affecting the binding interactions of the two complexes with the triplex.
两种含有不同辅助配体的钌（II）多吡啶配合物，[Ru(bpy)(dppz-Br)]（Ru1；bpy=2,2'-联吡啶，dppz-Br=7-Br-二吡啶并[3,2-a,2',3'-c]-吩嗪）和[Ru(dmb)(dppz-Br)]（Ru2；dmb=4,4'-二甲基-2,2'-联吡啶）已被合成并进行了表征。通过紫外可见光谱、荧光光谱、粘度测量以及圆二色性和热变性研究了 Ru1 和 Ru2 与 RNA 聚（U）•聚（A）*聚（U）三聚体的结合性质。分光光度研究和粘度测量表明，Ru1 和 Ru2 均通过嵌入模式与三聚体结合，熔融实验表明两种配合物均可有效增强三聚体的稳定性。然而，结果表明 Ru1 稳定第三链而不具有明显选择性，而在相同条件下，Ru2 优先与三聚体的第三链结合而不是 Watson-Crick 碱基配对的双链，从而显著稳定第三链。本研究结果表明，辅助配体 bpy 和 dmb 的细微差异应是影响两种配合物与三聚体结合相互作用的主要因素。
