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Single-Molecule Fluorescence Visualization of DNA Polymerase Dynamics at G-Quadruplexes
Published on: April 4, 2025
G-quadruplexes from human telomeric DNA: how many conformations in PEG containing solutions?
Luigi Petraccone1, Anna Malafronte, Jussara Amato
1Dipartimento di Chimica P. Corradini, Via Cintia, Università Federico II di Napoli, 80126, Naples, Italy. luigi.petraccone@unina.it
The Journal of Physical Chemistry. B
|January 25, 2012
Summary
Human telomeric DNA G-quadruplex formation is key for anticancer drugs. This study shows hybrid and parallel G-quadruplex structures coexist in cell-like conditions, challenging previous assumptions.
Area of Science:
- Biochemistry
- Structural Biology
- Medicinal Chemistry
Background:
- G-quadruplex structures in human telomeres are promising anticancer targets.
- Accurate G-quadruplex conformation data is crucial for structure-based drug design.
- Previous studies suggested polyethylene glycol (PEG) induces a complete conversion to parallel G-quadruplex.
Purpose of the Study:
- To kinetically and thermodynamically characterize human telomeric DNA conformational transitions in PEG.
- To investigate the influence of PEG concentration and molecular weight on G-quadruplex formation.
- To determine the folding timescales of different G-quadruplex conformations.
Main Methods:
- Conformational analysis of (TTAGGG)(4)TT and (TTAGGG)(8)TT DNA sequences in K+ solution with PEG.
- Kinetic and thermodynamic characterization of structural transitions.
- Exploration of crowding agents like Ficoll 400 and glycerol.
Main Results:
- Hybrid-type and parallel G-quadruplex conformations coexist at equilibrium in PEG at physiological temperature.
- The extent of structural conversion is dependent on PEG molecular weight.
- Parallel G-quadruplex folding occurs on the seconds timescale, slower than hybrid quadruplex folding (~ms).
Conclusions:
- The conversion to parallel G-quadruplex is not complete under physiological conditions simulated by PEG.
- The relative abundance of G-quadruplex conformations can be predicted based on temperature and time.
- Findings provide crucial insights for developing targeted anticancer therapies based on G-quadruplex structures.
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