title: A naked-eye on-off-on molecular "light switch" based on a reversible "conformational switch" of G-quadruplex DNA.
abstract: Herein, we report a new strategy for developing an on-off-on molecular "light switch" by utilizing the pH value to control the "conformational switch" of G-quadruplex DNA. A novel ruthenium(II) complex with an emission enhancement factor of 150 was synthesized and introduced to detect the switch by the naked eye. The "light switch" can be repeatedly cycled off and on through the addition of H(+) and OH(-), respectively. The conformational transitions of G-quadruplex DNA in K(+) solution at different pH values in the acidic region were evidenced by circular dichroism and fluorescence titrations. Computational calculations by applying density functional theory (DFT)/time-dependent DFT and molecular docking were also carried out to gain insight into the "light-switch" mechanism.
authors.affiliation: Department of Chemistry, Tongji University, Shanghai 200092, People's Republic of China.
authors.forename: Jun-Liang
authors.initials: JL
authors.lastname: Yao
authors.forename: Xing
authors.initials: X
authors.lastname: Gao
authors.forename: Wenliang
authors.initials: W
authors.lastname: Sun
authors.forename: Xue-Zhong
authors.initials: XZ
authors.lastname: Fan
authors.forename: Shuo
authors.initials: S
authors.lastname: Shi
authors.forename: Tian-Ming
authors.initials: TM
authors.lastname: Yao
mesh_terms: D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D005453:Fluorescence; D054856:G-Quadruplexes; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D011789:Quantum Theory; D012428:Ruthenium / Q000737:chemistry
chemical_list: D009942:Organometallic Compounds; D012428:Ruthenium; D004247:DNA