title: New pyridinium-based fluorescent dyes: A comparison of symmetry and side-group effects on G-Quadruplex DNA binding selectivity and application in live cell imaging.
abstract: A series of C1-, C2-and C3-symmetric pyridinium conjugates with different styrene-like side groups were synthesized and were utilized as G-quadruplex selective fluorescent probes. The new compounds were well-characterized. Their selectivity, sensitivity, and stability towards G-quadruplex were studied by fluorescence titration, native PAGE experiments, FRET and circular dichroism (CD) analyses. These new compounds investigated in the fluorescence assays were preferentially bound with G-quadruplex DNA compared with other type of nucleic acids and it is fascinating to realize the effects of molecular symmetry and associated side groups showing unexpectedly great influence on the fluorescent signal enhancement for the discrimination of G-quadruplexes DNA from other nucleic acids. This may correlate with the pocket symmetry and shape of the G-quadruplex DNA inherently. Among the compounds, a C2-symmetric dye (2,6-bis-((E)-2-(1H-indol-3-yl)-vinyl)-1-methylpyridin-1-ium iodide) with indolyl-groups substituted was screened out from the series giving the best selectivity and sensitivity towards G-quadruplexes DNA, particularly telo21, due to its high equilibrium binding constant (K=2.17×10(5)M(-1)). In addition, the limit of detection (LOD) of the dye to determine telo21 DNA in bioassays was found as low as 33nM. The results of the study give insight and certain crucial factors, such as molecular symmetry and the associated side groups, on developing of effective fluorescent dyes for G-quadruplex DNA applications including G-quadruplex structure stabilization, biosensing and clinical applications. The compound was also demonstrated as a very selective G-quadruplex fluorescent agent for living cell staining and imaging.
authors.affiliation: Institute of Natural Medicine and Green Chemistry, School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, PR China. Electronic address: luyj@gdut.edu.cn.
authors.forename: Yu-Jing
authors.initials: YJ
authors.lastname: Lu
authors.affiliation: Institute of Natural Medicine and Green Chemistry, School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, PR China.
authors.forename: Dong-Ping
authors.initials: DP
authors.lastname: Hu
authors.affiliation: Institute of Natural Medicine and Green Chemistry, School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, PR China.
authors.forename: Kun
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Department of Science and Environmental Studies, Centre for Education in Environmental Sustainability, The Hong Kong Institute of Education, 10 Lo Ping Road, Tai Po, Hong Kong SAR, PR China. Electronic address: wingleung@ied.edu.hk.
authors.forename: Wing-Leung
authors.initials: WL
authors.lastname: Wong
authors.affiliation: Department of Science and Environmental Studies, Centre for Education in Environmental Sustainability, The Hong Kong Institute of Education, 10 Lo Ping Road, Tai Po, Hong Kong SAR, PR China.
authors.forename: Cheuk-Fai
authors.initials: CF
authors.lastname: Chow
mesh_terms: D015374:Biosensing Techniques / Q000379:methods; D045744:Cell Line, Tumor; D002470:Cell Survival; D004247:DNA / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D054856:G-Quadruplexes; D006801:Humans; D008856:Microscopy, Fluorescence; D061848:Optical Imaging; D011726:Pyridinium Compounds / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: D005456:Fluorescent Dyes; D011726:Pyridinium Compounds; D004247:DNA
keywords: Cell imaging; Distyrylpyridinium dye; Fluorescence probe; G-Quadruplexes DNA; Telo21