title: [Ru(bpy)2(7-CH3-dppz)](2+) and [Ru(phen)2(7-CH3-dppz)](2+) as metallointercalators that affect third-strand stabilization of the poly(U)˙poly(A)*poly(U) triplex.
abstract: Stable RNA triplexes play key roles in many biological processes. However, due to Hoogsteen base pairing, triplexes are thermodynamically less stable than the corresponding duplexes. To understand the factors effecting the stabilization of RNA triplexes by octahedral ruthenium(ii) complexes, two Ru(ii) complexes, [Ru(bpy)2(7-CH3-dppz)](2+) (Ru) and [Ru(phen)2(7-CH3-dppz)](2+) (Ru), have been synthesized and characterized in this work. The interactions of the two Ru(ii) complexes with the poly(U)˙poly(A)*poly(U) triplex are investigated by spectrophotometry, spectrofluorometry, circular dichroism as well as viscometry. The results demonstrate that the two complexes are able to enhance the stability of the RNA triplex and serve as molecular "light switches" for the triplex. However, Ru and Ru affecting the stabilization of the third strand are significantly weaker than that of the Watson-Crick base-paired duplex, suggesting that the binding of the two complexes with the triplex is favored by the Watson-Crick base-paired duplex to a large extent. In addition, considering the nature of Ru and Ru, we presume that their binding differences may be due to different ancillary ligand effects. This study further advances our knowledge on the interaction of RNA triple-stranded structures with metal complexes, particularly with Ru(ii) complexes.
authors.affiliation: College of Chemistry, Xiangtan University, Xiangtan 411105, P. R. China. lfwyxh@yeah.net.
authors.forename: Wuzhi
authors.initials: W
authors.lastname: Tang
authors.affiliation: College of Chemistry, Xiangtan University, Xiangtan 411105, P. R. China. lfwyxh@yeah.net.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: College of Chemistry, Xiangtan University, Xiangtan 411105, P. R. China. lfwyxh@yeah.net and Key Lab of Environmentally Friendly Chemistry and Application in Ministry of Education, Xiangtan University, Xiangtan 411105, P. R. China.
authors.forename: Lifeng
authors.initials: L
authors.lastname: Tan
mesh_terms: D015082:2,2'-Dipyridyl / Q000031:analogs & derivatives* / Q000494:pharmacology; D009690:Nucleic Acid Conformation / Q000187:drug effects*; D009691:Nucleic Acid Denaturation; D009942:Organometallic Compounds / Q000494:pharmacology*; D011061:Poly A / Q000737:chemistry*; D011072:Poly U / Q000737:chemistry*; D012313:RNA / Q000737:chemistry*; D020871:RNA Stability / Q000187:drug effects; D013057:Spectrum Analysis; D013816:Thermodynamics; D014783:Viscosity
chemical_list: D009942:Organometallic Compounds; C103599:bis(bipyridyl)ruthenium(II); D011061:Poly A; D011072:Poly U; D015082:2,2'-Dipyridyl; D012313:RNA