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Updated: Jan 28, 2026
11:25
A G-quadruplex DNA-affinity Approach for Purification of Enzymatically Active G4 Resolvase1
Published on: March 18, 2017
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N-Methylmesoporphyrin IX Exhibits G-Quadruplex-Specific Photocleavage Activity.
Dominic McBrayer1, Michelle Schoonover1, Kimberly J Long2
1Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas, 107 W. Dean Keaton, Austin, TX, 78712, USA.
Chembiochem : a European Journal of Chemical Biology
|March 10, 2019
Summary
N-Methylmesoporphyrin IX (NMM) selectively photocleaves G-quadruplex (G4) DNA but not duplex DNA. Singlet oxygen generation does not appear to be the mechanism for this G4 photocleavage.
Area of Science:
- Biochemistry
- Molecular Biology
- Photochemistry
Background:
- N-Methylmesoporphyrin IX (NMM) is recognized as a G-quadruplex DNA (G4) ligand.
- Its G4 photocleavage activity remains largely unexplored.
Purpose of the Study:
- To investigate the G4 photocleavage activity of NMM.
- To determine the selectivity of NMM as a photocleavage agent for G4 structures versus duplex DNA.
- To elucidate the mechanism of NMM-induced G4 photocleavage.
Main Methods:
- PAGE analysis of photocleavage products.
- Comparison with TMPyP4 (a known nonselective DNA photocleavage agent).
- Singlet oxygen generation studies in H2O and D2O.
Main Results:
- NMM demonstrates high selectivity as a photocleavage agent for G4 structures, showing no significant cleavage of duplex DNA.
- Photocleavage sites on G4 DNA by NMM are comparable to those cleaved by TMPyP4.
- NMM generates singlet oxygen with both duplex and G4 DNA, but this is not involved in G4 photocleavage, as evidenced by lack of enhanced cleavage in D2O.
Conclusions:
- NMM is a selective photocleavage agent for G-quadruplex DNA.
- The mechanism of NMM-mediated G4 photocleavage does not involve singlet oxygen.
- NMM's G4 photocleavage activity warrants further investigation for potential applications.
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