Figure 5.

(A) CD titration plot of BQQ-neomycin with the Oxytricha Nova G-quadruplex DNA. The ratios of BQQ-neomycin to the quadruplex are indicated in the legend. (B) CD detected binding stoichiometry plot of BQQ-neomycin interacting with the Oxytricha Nova G-quadruplex DNA. (C) Control titration experiment of BQQ-Cl with the Oxytricha Nova G-quadruplex DNA. The DNA concentration used in the experiments was 10 μM/strand and both the experiments were performed in buffer 10 mM sodium cacodylate, 0.5 mM EDTA, 100 mM NaCl at pH 7.0 at 20°C. Small aliquots of ligand were serially added [as indicated on plots (A,C)] to the DNA solution. During the titration, the DNA solution was stirred with the added ligand for 5 min followed by another 5 min of equilibration time. The CD signal represents an average of three scans.