title: Investigation of the nanoviscosity effect of a G-quadruplex and single-strand DNA using fluorescence correlation spectroscopy.
abstract: Guanine (G)-quadruplexes are of interest because of their presence in the telomere sequence and the oncogene promoter region. Their diffusion and change of structure, especially in high viscosity solutions, are important for understanding their dynamics. G-quadruplexes may have less effective viscosity (nanoviscosity) when they are smaller than the solvent molecules. In this paper, we report the difference in the diffusion dynamics of the G-rich DNA sequences of single-strand DNA (ssDNA) and the G-quadruplex in aqueous, sucrose, and polyethylene glycol (PEG) solutions. From experiments with aqueous and sucrose solutions, we confirm that a simple diffusion model according to the viscosity is appropriate. In the PEG experiments, the nanoviscosity effect is observed according to PEG's molecular weight. In the PEG 200 solution, both the ssDNA and the G-quadruplex possess macroviscosity. In the PEG 10,000 solution, the G-quadruplex possesses nanoviscosity and the ssDNA possesses macroviscosity, whereas, in the PEG 35,000 solution, both ssDNA and the G-quadruplex possess nanoviscosity. The experimental results are consistent with the theoretical predictions.
authors.affiliation: Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, South Korea.
authors.forename: Dongkeun
authors.initials: D
authors.lastname: Lee
authors.affiliation: Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, South Korea.
authors.forename: Minjung
authors.initials: M
authors.lastname: Kim
authors.affiliation: Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, South Korea.
authors.forename: Soo Yong
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, South Korea.
authors.forename: Hyosup
authors.initials: H
authors.lastname: Shin
authors.affiliation: Department of Physics, University of Ulsan, Ulsan 680-749, South Korea.
authors.forename: Sok Won
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Department of Physics, University of Incheon, Incheon 406-772, South Korea.
authors.forename: Inho
authors.initials: I
authors.lastname: Park
mesh_terms: D004277:DNA, Single-Stranded / Q000737:chemistry*; D054856:G-Quadruplexes; D008970:Molecular Weight; D011092:Polyethylene Glycols / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D014783:Viscosity
chemical_list: D004277:DNA, Single-Stranded; D011092:Polyethylene Glycols