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Single-molecule Manipulation of G-quadruplexes by Magnetic Tweezers
Published on: September 19, 2017
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Fluorescence Turn-Off Ligand for Parallel G-Quadruplexes
Joanna Nowak-Karnowska1, Agata Głuszyńska1, Joanna Kosman1,2
1Department of Bioanalytical Chemistry, Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland.
Molecules (Basel, Switzerland)
|August 29, 2024
Summary
The fluorescent ligand 9-methoxyluminarine (9-MeLM) binds parallel G-quadruplexes (G4s) in human DNA promoters. This selective binding allows 9-MeLM to function as a fluorescence turn-off probe for G4 detection.
Area of Science:
- Biochemistry
- Molecular Biology
- Genomics
Background:
- Parallel-stranded G-quadruplex (G4) structures are prevalent in human promoter regions.
- These G4 structures play roles in gene regulation.
Purpose of the Study:
- To investigate the binding interactions of the fluorescent ligand 9-methoxyluminarine (9-MeLM) with various parallel G-quadruplexes.
- To evaluate 9-MeLM as a potential selective probe for parallel G4s.
Main Methods:
- Spectroscopic techniques including fluorescence and circular dichroism (CD) titrations.
- UV melting profile analysis to assess thermal stability upon ligand binding.
Main Results:
- 9-MeLM demonstrated similar binding affinities across different parallel G-quadruplexes.
- Binding constants for 9-MeLM with various parallel G4s were quantified.
- Evidence suggests preferential interaction of 9-MeLM with the 3' end of the c-MYC G-quadruplex promoter.
- Significant fluorescence quenching of 9-MeLM upon binding to G4s was observed.
Conclusions:
- 9-MeLM is a selective fluorescent probe for parallel G-quadruplexes.
- The observed fluorescence turn-off mechanism enables sensitive detection of parallel G4 structures.
- 9-MeLM shows potential for studying G4s in biological contexts, such as the c-MYC promoter.
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