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. 2024 Feb 10;52(5):2142–2156. doi: 10.1093/nar/gkae073

Figure 3.

Figure 3.

G4 exhibits a strong inhibitory effect on the activity of Top1 in relaxing negatively supercoiled DNA. (A) A schematic illustration describes the process of Top1 unwinding a supercoiled plasmid (SC-) to a relaxed plasmid (R), and the interference of this process by G4. (B) Detection of the activity of the purified human Top1 using a plasmid relaxation assay in the presence of 5 μM of 11 core G4s (CSTB, MYC, C-Kit, C9orf72, BCL-2, Tel, MYOG, PDGFRB, T1B1, T4B1, B4-dx2) and a non-G4 ssDNA (Supplementary Table S2). (C) Detection of the activity of the purified human Top1 using a plasmid relaxation assay in the presence of 1 μM of 11 G4s (CSTB, MYC, C-Kit, C9orf72, BCL-2, Tel, MYOG, PDGFRB, T1B1, T4B1, B4-dx2) in dsDNA or a non-G4 dsDNA (Supplementary Table S3). A negatively supercoiled pGL3-basic plasmid served as the substrate for Top1. The relaxed and supercoiled plasmids were labeled as R and SC–, respectively.