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Updated: Apr 19, 2026
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Single-Molecule Fluorescence Visualization of DNA Polymerase Dynamics at G-Quadruplexes
Published on: April 4, 2025
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A photoreactive G-quadruplex ligand triggered by green light
Matteo Nadai1, Filippo Doria, Luca Germani
1Department of Molecular Medicine, University of Padua, Via Gabelli 63, 35121 Padua (Italy).
Chemistry (Weinheim an Der Bergstrasse, Germany)
|December 17, 2014
Summary
Researchers developed a light-activated dye that selectively modifies G-quadruplex (G4) DNA. This offers a precise method for nucleic acid research and potential cellular applications.
Area of Science:
- Biochemistry
- Molecular Biology
- Photochemistry
Background:
- G-quadruplex (G4) structures are crucial in telomere maintenance and gene regulation.
- Targeting G4 structures offers therapeutic and diagnostic potential.
- Selective modification of nucleic acids is essential for molecular biology tools.
Purpose of the Study:
- To develop a photoreactive molecular dye for selective G-quadruplex (G4) targeting.
- To investigate the mechanism of G4 modification upon photoactivation.
- To explore potential applications in nucleic acid research and cellular studies.
Main Methods:
- Synthesis of a photoreactive molecular dye.
- Photoactivation using green light (532 nm).
- Laser-flash photolysis for intermediate detection.
- Analysis of DNA modification selectivity using mutated analogues.
Main Results:
- The dye selectively covalently modified the human telomeric G-quadruplex (Tel22) with up to 64% efficiency.
- Phenoxyl radical intermediate was generated and detected, targeting loop thymine residues.
- High selectivity for G4 over single- and double-stranded DNA was demonstrated.
Conclusions:
- Photoactivation of the dye enables selective covalent modification of G-quadruplex DNA.
- The mechanism involves a phenoxyl radical intermediate targeting specific DNA sites.
- This approach may lead to non-invasive tools for nucleic acid tagging and cellular applications.
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