title: Chemical control of the DNA light switch: cycling the switch ON and OFF.
abstract: The emission of the DNA light-switch complex [Ru(bpy)2(tpphz)]2+ (bpy = 2,2'-bipyridine, tpphz = tetrapyrido[3,2-a:2',3'-c:3' ',2' '-h:2' '',3' ''-j]phenazine) can be reversibly turned ON and OFF over several cycles. The tpphz and taptp (taptp = 4,5,9,18-tetraazaphenanthreno[9,10-b] triphenylene) ligands in [Ru(bpy)2(tpphz)]2+ and [Ru(bpy)2(taptp)]2+, respectively, intercalate between the DNA bases, and a 50-fold increase in emission intensity of [Ru(bpy)2(tpphz)]2+ is observed upon DNA intercalation. The [Ru(bpy)2(tpphz)]2+ DNA light switch can be turned OFF statically in the presence of Co2+, Ni2+, and Zn2+, and the emission can be fully restored by the addition of EDTA. Cycling of the DNA light switch OFF and ON can be accomplished through the successive introduction of Co2+ and EDTA, respectively, to solutions of DNA-bound [Ru(bpy)2(tpphz)]2+. Owing to the absence of additional coordination sites, the emission of DNA-intercalated [Ru(bpy)2(taptp)]2+ is not quenched by transition metal ions in solution. To our knowledge, this work presents the first example of a reversible DNA light switch.
authors.affiliation: Department of Chemistry, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Yao
authors.initials: Y
authors.lastname: Liu
authors.forename: Abdellatif
authors.initials: A
authors.lastname: Chouai
authors.forename: Natalya N
authors.initials: NN
authors.lastname: Degtyareva
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Lutterman
authors.forename: Kim R
authors.initials: KR
authors.lastname: Dunbar
authors.forename: Claudia
authors.initials: C
authors.lastname: Turro
mesh_terms: D004247:DNA / Q000737:chemistry*; D007364:Intercalating Agents / Q000737:chemistry; D008027:Light
chemical_list: D007364:Intercalating Agents; D004247:DNA