title: Human telomeric G-quadruplex formed from duplex under near physiological conditions: spectroscopic evidence and kinetics.
abstract: The structural interconversion between the G-quadruplex and duplex in vivo is an important subject. In the present study, we used human telomeric DNA duplex composed of GGG(TTAGGG)(3)/CCC(TAACCC)(3) as a model system to investigate its properties under near physiological conditions by spectroscopic methods. Circular dichroism and fluorescence spectra demonstrated that G-quadruplex structure can be formed from duplex at near physiological pH (pH 7.4), salt concentration (150 mM K(+)), and temperature (37 degrees C) in the presence of molecular crowding agent PEG (400 g/l), whereas the G-quadruplex structure cannot be formed at 25 degrees C in buffer containing 150 mM K(+) in the presence of PEG. It is found that the formation rate of G-quadruplex structure depends on the temperature and the concentrations of both PEG and K(+). This work suggests that human telomeric G-quadruplex structure may be potentially formed from Watson-Crick duplex in vivo.
authors.affiliation: State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhou
authors.forename: Chunying
authors.initials: C
authors.lastname: Wei
authors.forename: Guoqing
authors.initials: G
authors.lastname: Jia
authors.forename: Xiuli
authors.initials: X
authors.lastname: Wang
authors.forename: Zhaochi
authors.initials: Z
authors.lastname: Feng
authors.forename: Can
authors.initials: C
authors.lastname: Li
mesh_terms: D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D054856:G-Quadruplexes; D006801:Humans; D007700:Kinetics; D009690:Nucleic Acid Conformation; D013050:Spectrometry, Fluorescence; D016615:Telomere / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics
chemical_list: D004247:DNA