title: Interaction of [Ru(bpy)2(dppz)]2+ with human telomeric DNA: preferential binding to G-quadruplexes over i-motif.
abstract: Inspired by the enormous importance attributed to the structure and function of human telomeric DNA, we focus our attention on the interaction of [Ru(bpy)(2)(dppz)](2+) with the guanine-rich single-strand oligomer 5'-AGGGTTAGGGTTAGGGTTAGGG-3' (22AG) and the complementary cytosine-rich strand (22CT). In Na(+) buffer, 22AG may adopt an antiparallel basket quadruplex, whereas, it favours a mixed parallel/antiparallel structure in K(+) buffer. 22CT may self-associate at acidic pH into an i-motif. In this paper, the interaction between [Ru(bpy)(2)(dppz)](2+) and each unusual DNA was evaluated. It was interesting that [Ru(bpy)(2)(dppz)](2+) could promote the human telomeric repeat 22AG to fold into intramolecular antiparallel G-quadruplex without any other cations. What's more, [Ru(bpy)(2)(dppz)](2+) was found to have a strong preference for binding to G-quadruplexes that were induced through either Na(+) or K(+), while weak binding to i-motif was observed. The results also indicated that [Ru(bpy)(2)(dppz)](2+) could serve as a prominent molecular "light switch" for both G-quadruplexes, revealing a potential application of the title complex in luminescent signaling of G-quadruplex DNA.
authors.affiliation: Department of Chemistry, Tongji University, Shanghai, PR China. shishuo@tongji.edu.cn
authors.forename: Shuo
authors.initials: S
authors.lastname: Shi
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Geng
authors.forename: Juan
authors.initials: J
authors.lastname: Zhao
authors.forename: Tianming
authors.initials: T
authors.lastname: Yao
authors.forename: Chaoran
authors.initials: C
authors.lastname: Wang
authors.forename: Danjing
authors.initials: D
authors.lastname: Yang
authors.forename: Lengfeng
authors.initials: L
authors.lastname: Zheng
authors.forename: Liangnian
authors.initials: L
authors.lastname: Ji
mesh_terms: D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D054856:G-Quadruplexes / Q000187:drug effects*; D006801:Humans; D009690:Nucleic Acid Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D010619:Phenazines / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D016615:Telomere / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D010619:Phenazines; C077849:bis(2,2'-bipyridyl)(dipyrido(3,2-alpha-2',3'-c)phenazine)ruthenium (II); D004247:DNA