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Updated: Feb 6, 2026

Single-Molecule Fluorescence Visualization of DNA Polymerase Dynamics at G-Quadruplexes
Published on: April 4, 2025
Supramolecular complex binding to G-quadruplex DNA: Berberine encapsulated by a planar side arm-tethered
Soundrapandian Suganthi1, Ramasamy Sivaraj1, Paulraj Mosae Selvakumar1
1a Department of Chemistry , Karunya Institute of Technology and Sciences , Coimbatore , India.
Abstract:
G-quadruplex-binders have the plausible potential to act as anticancer agents. Herein, the mode of binding of a synthesized fluorenyl derivative of β-cyclodextrin with a duplex and G-quadrulex DNAs has been investigated. Moreover, the loading of the well-known G-quadruplex binder, berberine, in the β-cyclodextrin derivative using 2-dimensional rotating-frame Overhauser effect spectroscopy is studied. The intensity of proton NMR signals is weakened on the β-cyclodextrin derivative's interaction with the quadruplexes. Binding constants are reported for each binding of the ligands to calf thymus DNA, kit22, telo24, and myc22 employing fluorescence spectroscopy. A general trend of fluorescence response (quenching) on the β-cyclodextrin derivative to the DNAs is modified when the berberine molecule is loaded in the host structure. Despite berberine binds to the macromolecular target strongly, its host-guest association with the cavity of β-cyclodextrin diminishes the binding strength. A significant difference between the binding strengths of the ligands with duplex and quadruplex structures is observed. Communicated by Ramaswamy H. Sarma.
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