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Updated: May 3, 2026
Single-molecule Manipulation of G-quadruplexes by Magnetic Tweezers
Published on: September 19, 2017
Dinuclear nickel(II) triple-stranded supramolecular cylinders: syntheses, characterization and G-quadruplexes binding
Xin-Xin Xu1, Jing-Jing Na1, Fei-Fei Bao1
1School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, PR China.
Abstract:
Three dinuclear nickel triple-stranded supramolecular cylinders [Ni2(L1)3][ClO4]4 (1), [Ni2(L2)3][ClO4]4 (2) and [Ni2(L3)3][ClO4]4 (3) with bis(pyridylimine) Schiff base containing triphenyl groups in the spacers as ligands were synthesized and characterized. The human telomeric G-quadruplexes binding properties of cylinders 1-3 were evaluated by means of UV-Vis spectroscopy, circular dichroism (CD) spectroscopy and fluorescence resonance energy transfer (FRET) melting assay. UV-Vis studies revealed that the supramolecular cylinders 1-3 could bind to G-quadruplex DNA with high binding constants (Kb values ranging from 0.11-2.2×10(6) M(-1)). FRET melting studies indicated that the cylinders 1-3 had much stronger stabilizing effect on G-quadruplex DNA (ΔTm up to 24.5°C) than the traditional cylinder Ni2L3(4+) just containing diphenylmethane spacers (ΔTm=10.6 °C). Meanwhile, cylinders 1-3 were found to have a modest degree of selectivity for the quadruplex DNA versus duplex DNA in competition FRET assays. Moreover, CD spectroscopy revealed that complex 1 could induce G-quadruplex formation in the absence of metal ions solution and convert antiparallel G-quadruplex into hybrid structure in Na(+) solution. These results provided a new insight into the development of supramolecular cylinders as potential anticancer drugs targeting G-quadruplex DNA.
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