Selective Binding of Distamycin A Derivative to G-Quadruplex Structure [d(TGGGGT)]₄

Figure 3

Expanded region of the ¹H-NMR titration of d(CGCGAATTCGCG)₂ with derivative 1 (700 MHz, 𝑇=25^∘C). 1 mM (4 mM single strand concentration), in 0.2 ml (H₂O/D₂O 9 : 1) buffer solution having 10 mM KH₂PO₄, 70 mM KCl, 0.2 mM EDTA, and pH7.0. Equivalents of the drug are reported on the left of each spectrum. Residues that are slightly affected by the binding are indicated.