Fluorescent amplifying recognition for DNA G-quadruplex folding with a cationic conjugated polymer: a platform for homogeneous potassium detection.
Single-stranded DNA with G-rich sequences can fold into secondary structures, G-quadruplexes, via intramolecular hydrogen-bonding interactions. This conformational change can be detected by a homogeneous assay method based on fluorescence resonance energy transfer (FRET) from a water-soluble cationic conjugated polymer (CCP) to a fluorescein chromophore labeled at the terminus of the G-quadruplex DNA. The space charge density around the DNA controls the efficiency of FRET from the CCP to the fluorescein. The higher FRET efficiency for the CCP/G-quadruplex pair is correlated to the stronger electrostatic interactions between the more condensed G-quadruplex and the CCP in comparison to the CCP/ssDNA pair. Since the potassium ion can specifically bind to the G-quadruplex DNA, the G-quartet-DNA/CCPs assembly can also be used as a platform to sense the potassium ion in water with high selectivity and sensitivity.
He
Fang
F
CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, PR China.
Tang
Yanli
Y
Wang
Shu
S
Li
Yuliang
Y
Zhu
Daoben
D
D015374:Biosensing Techniques / Q000379:methods; D002412:Cations; D004247:DNA / Q000737:chemistry*; D004277:DNA, Single-Stranded / Q000737:chemistry*; D031541:Fluorescence Resonance Energy Transfer; D005456:Fluorescent Dyes / Q000737:chemistry; D054856:G-Quadruplexes; D009690:Nucleic Acid Conformation; D011188:Potassium / Q000737:chemistry*; D012680:Sensitivity and Specificity; D014867:Water / Q000737:chemistry
D002412:Cations; D004277:DNA, Single-Stranded; D005456:Fluorescent Dyes; D014867:Water; D004247:DNA; D011188:Potassium