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Updated: Jan 28, 2026

A G-quadruplex DNA-affinity Approach for Purification of Enzymatically Active G4 Resolvase1
Published on: March 18, 2017
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.
Abstract:
N-Methylmesoporphyrin IX (NMM) has long been known as a G-quadruplex DNA (G4) ligand. However, there has been little investigation into its G-quadruplex photocleavage activity. Herein, we demonstrate that NMM is a highly selective photocleavage agent for G4 structures but not duplex DNA. Analysis of the cleavage products by PAGE demonstrates that G4 photocleavage by NMM occurs at sites similar to those cleaved by TMPyP4, a nonselective DNA photocleavage agent. Although NMM is shown here to generate singlet oxygen in the presence of both duplex and G4, the lack of increased photocleavage in D2 O indicated that singlet oxygen is not involved in the photocleavage of G4 by NMM.
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