title: Quadruplex-to-duplex transition of G-rich oligonucleotides probed by cationic water-soluble conjugated polyelectrolytes.
abstract: G-quartet DNA converts to duplex form in the presence of its complementary strand. This conformational change can be detected in real time by a homogeneous assay method based on the signal amplification of conjugated polyelectrolytes and the specific interaction of intercalating dyes with double-stranded DNA (dsDNA). The probe solution contains a cationic, conjugated polymer (CCP), G-quadruplex labeled with a fluorescein at the 5'-terminus (G-quadruplex-Fl), and ethidium bromide (EB). The addition of a complementary target results in the transition from G-quadruplex to duplex (dsDNA-Fl) and EB intercalation within the duplex structure. Excitation of the CCP leads to energy transfer from CCP to dsDNA-Fl (FRET-1) and then energy transfer from dsDNA-Fl to EB (FRET-2). Increasing the number of mismatched bases discourages dsDNA formation, which is detected in the assay.
authors.affiliation: Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China.
authors.forename: Fang
authors.initials: F
authors.lastname: He
authors.forename: Yanli
authors.initials: Y
authors.lastname: Tang
authors.forename: Minghui
authors.initials: M
authors.lastname: Yu
authors.forename: Fude
authors.initials: F
authors.lastname: Feng
authors.forename: Lingling
authors.initials: L
authors.lastname: An
authors.forename: Huan
authors.initials: H
authors.lastname: Sun
authors.forename: Shu
authors.initials: S
authors.lastname: Wang
authors.forename: Yuliang
authors.initials: Y
authors.lastname: Li
authors.forename: Daoben
authors.initials: D
authors.lastname: Zhu
authors.forename: Guillermo C
authors.initials: GC
authors.lastname: Bazan
mesh_terms: D002412:Cations; D004247:DNA / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry; D019793:Fluorescein / Q000737:chemistry; D006147:Guanine / Q000737:chemistry; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry*; D012995:Solubility; D013050:Spectrometry, Fluorescence; D014867:Water
chemical_list: D002412:Cations; D004573:Electrolytes; D009841:Oligonucleotides; D014867:Water; D006147:Guanine; D004247:DNA; D019793:Fluorescein