title: [Ru(bpy)2dppz-idzo]2+: a colorimetric molecular "light switch" and powerful stabilizer for G-quadruplex DNA.
abstract: A new ruthenium complex, [Ru(bpy)2dppz-idzo](2+) (bpy = 2,2'-bipyridine, dppz-idzo = dipyrido-[3,2-a:2',3'-c] phenazine-imidazolone), was synthesized and characterized. The luminescent titrations showed that the Ru-complex exhibited an outstanding "light switch" effect with an emission enhancement factor of about 300 in the presence of G-quadruplex DNA in a K(+) solution. This remarkable "light switch" behavior can even be observed by the naked eye under irradiation with UV light. To get an insight into the "light switch" mechanism, quantum-chemical calculations were performed based on the DFT/TDDFT/PCM method at the B3LYP/6-31G* level. Furthermore, the CD titrations and thermal melting experiments indicated that [Ru(bpy)2dppz-idzo](2+) could not only induce the formation of an antiparallel G-quadruplex structure in the absence of monocations, but also has the ability to stabilize the G-quadruplex architecture, implying potential applications in anticancer therapeutics. Both the "light switch" effect and the structure stabilization ability of [Ru(bpy)2dppz-idzo](2+) were found to be superior to the well-known DNA molecular "light switch" [Ru(bpy)2dppz](2+). Finally, a "sandwich-like" binding model was proposed on the basis of molecular docking simulations.
authors: Department of Chemistry, Tongji University, Shanghai, China.
authors: Jun-Liang
authors: JL
authors: Yao
authors: Xing
authors: X
authors: Gao
authors: Wenliang
authors: W
authors: Sun
authors: Shuo
authors: S
authors: Shi
authors: Tian-Ming
authors: TM
authors: Yao
mesh_terms: D001665:Binding Sites; D002942:Circular Dichroism; D003124:Colorimetry; D054856:G-Quadruplexes; D007477:Ions / Q000737:chemistry; D008968:Molecular Conformation; D062105:Molecular Docking Simulation; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010619:Phenazines / Q000138:chemical synthesis / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry; D011789:Quantum Theory; D014466:Ultraviolet Rays
chemical_list: D007477:Ions; D009942:Organometallic Compounds; D010619:Phenazines; C077849:bis(2,2'-bipyridyl)(dipyrido(3,2-alpha-2',3'-c)phenazine)ruthenium (II); D011188:Potassium