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Updated: Jun 25, 2026
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Single-Molecule Fluorescence Visualization of DNA Polymerase Dynamics at G-Quadruplexes
Published on: April 4, 2025
Natural isoflavones regulate the quadruplex-duplex competition in human telomeric DNA
Jin-li Zhang1, Yan Fu, Lin Zheng
1Key Laboratory of Systems Bioengineering, Ministry of Education, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, China.
Nucleic Acids Research
|March 6, 2009
Summary
Natural isoflavones stabilize human telomeric G-quadruplex DNA while destabilizing its Watson-Crick duplex. This selective interaction, particularly with daidzin, influences DNA structure and competition, offering insights into telomere regulation.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Human telomeric DNA exists in G-quadruplex and Watson-Crick duplex forms.
- These structures compete for DNA, influencing telomere stability and function.
- Natural compounds like isoflavones may modulate this structural competition.
Purpose of the Study:
- To investigate the effects of natural isoflavones on the structural competition between human telomeric G-quadruplex and its corresponding Watson-Crick duplex.
- To elucidate the molecular mechanisms underlying isoflavone-DNA interactions.
Main Methods:
- Circular dichroism (CD) spectroscopy
- Electrospray ionization mass spectrometry (ESI-MS)
- Fluorescence quenching assays
- CD stopped-flow kinetics
- UV-Vis spectroscopy
- Molecular modeling
Main Results:
- Isoflavones preferentially stabilize the G-quadruplex structure over the Watson-Crick duplex.
- This discrimination is enhanced under molecular crowding conditions.
- Daidzin significantly slows the dissociation rate of the G-quadruplex in the presence of K+ ions.
- Daidzin induces a structural transition of the G-quadruplex to an antiparallel conformation.
Conclusions:
- Natural isoflavones exhibit selective binding and structural modulation of human telomeric DNA.
- Isoflavones can shift the equilibrium towards G-quadruplex formation, impacting telomeric DNA structure.
- This study provides the first evidence of isoflavone recognition of G-quadruplex conformational polymorphism, suggesting potential regulatory roles in telomere biology.
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