title: Structural transition from the random coil to quadruplex of AG(3)(T(2)AG(3))(3) induced by Zn(2+).
abstract: Structures of G-quadruplex DNAs can be typically stabilized by monovalent cations such as K(+), Na(+). Some divalent and trivalent cations, such as Sr(2+), Pb(2+), Tb(3+) and Eu(3+), can also induce the formation of G-quadruplex DNA. Here we show that Zn(2+) can induce the human telomeric sequence AG(3)(T(2)AG(3))(3) to fold the G-quadruplex structure by UV absorbance difference spectra and circular dichroism (CD) spectroscopy. At micromolar concentrations, the Zn(2+)-induced changes in the UV absorbance difference spectra and CD spectra are the characteristics of antiparallel G-quadruplexes although the long wavelength CD maximum is around 285 nm rather than the typical value of 295 nm. The binding stoichometry of Zn(2+) per one AG(3)(T(2)AG(3))(3) molecule is four. To our knowledge, the structural transition of human telomeric sequence induced by Zn(2+) was observed for the first time.
authors.affiliation: Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Molecular Science, Shanxi University, Taiyuan China. weichuny@sxu.edu.cn
authors.forename: Chunying
authors.initials: C
authors.lastname: Wei
authors.forename: Qian
authors.initials: Q
authors.lastname: Tang
authors.forename: Can
authors.initials: C
authors.lastname: Li
mesh_terms: D001483:Base Sequence; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D054856:G-Quadruplexes / Q000187:drug effects*; D006801:Humans; D009690:Nucleic Acid Conformation / Q000187:drug effects; D013056:Spectrophotometry, Ultraviolet; D016615:Telomere; D015032:Zinc / Q000494:pharmacology*
chemical_list: D004247:DNA; D015032:Zinc