Interaction of ruthenium(Ⅱ) polypyridyl complexes [Ru(phen)2(L)]2+ (L = PIP, p-HPIP and m-HPIP) with RNA poly(A)•poly(U): Each complex unexpectedly exhibiting a destabilizing effect on RNA.

Ru(II) complexes [Ru(phen) 2 (PIP)]2+ (Ru 1), [Ru(phen) 2 (p-HPIP)]2+ (Ru 2), and [Ru(phen) 2 (m-HPIP)]2+ (Ru 3) have been synthesized and characterized in this work. Their binding properties of the RNA duplex poly(A)•poly(U) have been investigated. The obtained results show that the three Ru(Ⅱ) complexes bind to the RNA duplex poly(A)•poly(U) by intercalation, and destabilize the RNA duplex. [Display omitted] • Complexes [Ru(phen) 2 L]2+ (Ru 1 , L = PIP; Ru 2 , L = p-HPIP; Ru 3 , L = m-HPIP) were synthesized. • Binding of the three complexes with RNA poly(A)•poly(U) were investigated. • The three complexes destabilize RNA poly(A)•poly(U). • This work reports for the first time small molecules capable of destabilizing an RNA duplex. To further explore the binding properties of Ru(Ⅱ) polypyridine complexes with RNA, three Ru(Ⅱ) complexes [Ru(phen) 2 (PIP)]2+ (Ru 1), [Ru(phen) 2 (p-HPIP)]2+ (Ru 2), and [Ru(phen) 2 (m- HPIP)]2+ (Ru 3) have been synthesized and characterized in this work. The binding properties of three Ru(Ⅱ) complexes with RNA duplex poly(A)•poly(U) have been investigated by spectral and viscosity experiments. These studies all support that these three Ru(Ⅱ) complexes bind to poly RNA duplex poly(A)•poly(U) by intercalation, and Ru 1 without substituents has a stronger binding affinity for poly(A)•poly(U). Interestingly, the thermal melting experiments show that these three Ru(Ⅱ) complexes all destabilize RNA duplex poly(A)•poly(U), and the destabilizing effect can be explained by the conformational changes of duplex structure induced by intercalating agents. To the best of our knowledge, this work report for the first time a small molecule capable of destabilizing an RNA duplex, which reflects that the substitution effect of intercalated ligands has an important influence on the affinity of Ru(Ⅱ) complexes to RNA duplex, and that not all Ru(Ⅱ) complexes show thermal stability effects on an RNA duplex. [ABSTRACT FROM AUTHOR]