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Updated: Mar 20, 2026

Single-Molecule Fluorescence Visualization of DNA Polymerase Dynamics at G-Quadruplexes
Published on: April 4, 2025
G-quadruplex vs. duplex-DNA binding of nickel(II) and zinc(II) Schiff base complexes
Riccardo Bonsignore1, Alessio Terenzi2, Angelo Spinello1
1Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche, Viale delle Scienze, Edificio 17, 90128, Palermo, Italy; Istituto EuroMediterraneo di Scienza e Tecnologia, Piazzetta Briuccia, 20-21, 90139, Palermo, Italy.
Abstract:
Novel nickel(II) (1) and zinc(II) (2) complexes of a Salen-like ligand, carrying a pyrimidine ring on the N,N' bridge, were synthesized and characterized. Their interaction with duplex and G-quadruplex DNA was investigated in aqueous solution through UV-visible absorption, circular dichroism and viscometry measurements. The results obtained point out that, while the zinc(II) complex does not interact with both duplex and G-quadruplex DNA, the nickel(II) complex 1 binds preferentially to G-quadruplex respect to duplex-DNA, with values of the DNA-binding constants, Kb, 2.6×10(5)M(-1) and 3.5×10(4)M(-1), respectively. Molecular dynamics simulations provided an atomic level model of the top-stacking binding occurring between 1 and hTelo (a 22-mer sequence oligonucleotide) in G-quadruplex conformation.
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