title: Biophysical insights into the interaction of Ru(II) polypyridyl complexes with the RNA triplex poly(U)•poly(A)*poly(U). Intercalative ligand shape effect on third-strand stabilization.
abstract: To explore the correlating thermodynamic factors to the structural aspects that account for the stability of the RNA triplex, two functional Ru(II) complexes containing the same ancillary ligands and different intercalative ligands, [Ru(bpy)(2)(mip)](2+) (bpy=2,2'-bipyridine, mip=2'-(3",4"-methylene-dioxyphenyl)imidazo[4',5'-f][1,10]phenanthroline) and [Ru(bpy)(2)(bdip)](2+) (bdip=2-(1,3-benzodioxol-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline) have been synthesized. The binding properties of [Ru(bpy)(2)(mip)](2+) and [Ru(bpy)(2)(bdip)](2+) to the RNA triplex poly(U)•poly(A)*poly(U) have been investigated by various biophysical techniques and quantum chemistry calculations. Compared with [Ru(bpy)(2)(bdip)](2+), remarkably higher binding and stabilization of the triplex RNA structure by [Ru(bpy)(2)(mip)](2+) is achieved upon changing the substituent positions on the intercalative ligand. The result reveals that the intercalative ligand shape plays a critical role in third-strand stabilization.
authors.affiliation: College of Chemistry, Xiangtan University, Xiangtan 411105, PR China. lfwyxh@yahoo.com.cn
authors.forename: Lifeng
authors.initials: L
authors.lastname: Tan
authors.forename: Lingjun
authors.initials: L
authors.lastname: Xie
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Sun
authors.forename: Leli
authors.initials: L
authors.lastname: Zeng
authors.forename: Guang
authors.initials: G
authors.lastname: Yang
mesh_terms: D001703:Biophysics; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D011061:Poly A / Q000737:chemistry; D011072:Poly U / Q000737:chemistry; D012313:RNA / Q000737:chemistry* / Q000378:metabolism; D012428:Ruthenium / Q000737:chemistry; D017975:Ruthenium Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D013050:Spectrometry, Fluorescence
chemical_list: D017975:Ruthenium Compounds; D011061:Poly A; D011072:Poly U; D012313:RNA; D012428:Ruthenium