College of Chemistry, Xiangtan University, Xiangtan 411105, People's Republic of China.
Academic Affairs Office, Xiangtan University, Xiangtan 411105, People's Republic of China.
Int J Biol Macromol. 2022 Jun 1;209(Pt B):1648-1655. doi: 10.1016/j.ijbiomac.2022.04.091. Epub 2022 Apr 27.
Two Ru(II) complexes containing different substituents, [Ru(phen)(7-CH-dppz)] (Ru1) and [Ru(phen)(7-Br-dppz)] (Ru2), have been synthesized in this study. The binding properties of Ru1 and Ru2 with the duplex RNA poly(U)•poly(A) (where "•" denotes the Watson - Crick base pairing) have been researched by biophysical techniques and viscosity measurements. Analysis of spectral titrations and viscosity measurements indicate that Ru1 and Ru2 bind to the duplex via intercalative, and the binding affinity of Ru1 with the duplex is remarkably higher than that of Ru2. Furthermore, fluorescence emission spectra demonstrates that although complexes Ru1 and Ru2 can act as molecular "light switches" for the duplex RNA, alters in fluorescence emission of Ru1 and Ru2 are prominent differences, and the effectiveness of Ru1 is more remarkable compared with that of Ru2. The melting experiments suggest that the duplex RNA stabilizing effects of Ru1 and Ru2 differ from each other, among them, complex Ru1 can obviously enhance the stability of the duplex RNA, while Ru2 has only a slightly stabilizing effect for the duplex RNA, indicating that Ru1 preferentially binds to RNA duplex over Ru2. The obtained results indicate that subtle modifications of the intercalative ligand of Ru(II) polypyridyl complex with either methyl or bromide group have a significant effect on the duplex-binding discrimination.
本研究合成了两种含有不同取代基的 Ru(II) 配合物，[Ru(phen)(7-CH-dppz)]（Ru1）和[Ru(phen)(7-Br-dppz)]（Ru2）。通过物理化学技术和粘度测量研究了 Ru1 和 Ru2 与双链 RNA 聚（U）•聚（A）（其中“•”表示 Watson-Crick 碱基配对）的结合特性。光谱滴定和粘度测量分析表明，Ru1 和 Ru2 通过嵌入方式与双链结合，Ru1 与双链的结合亲和力明显高于 Ru2。此外，荧光发射光谱表明，尽管配合物 Ru1 和 Ru2 可以作为双链 RNA 的分子“光开关”，但 Ru1 和 Ru2 的荧光发射变化存在显著差异，并且 Ru1 的效果比 Ru2 更为显著。熔解实验表明，Ru1 和 Ru2 对双链 RNA 的稳定作用不同，其中配合物 Ru1 能明显增强双链 RNA 的稳定性，而 Ru2 对双链 RNA 只有轻微的稳定作用，表明 Ru1 优先与 RNA 双链结合，而不是 Ru2。实验结果表明，Ru(II) 多吡啶配合物的嵌入配体的细微修饰对双链结合的选择性有显著影响。
