Table 3. Dissociation Constants (K_d) for Binding of 1–4 to 20-mer Duplex, G-Quadruplex (G4), and Three-Way Junction (3WJ) DNA Measured Using Cy5.5-Labeled Oligonucleotides and FRET^a.

	duplex		G4		3WJ
complex	Kd (μM)	r (Å)	Kd (μM)	r (Å)	Kd (μM)	r (Å)
1	2.8 ± 0.9	33.5	3.9 ± 1.3	26.8	4.3 ± 0.9	37.4
2	2.3 ± 0.5	33.1	3.8 ± 1.7	30.0	4.4 ± 0.7	35.0
3	6.3 ± 0.3	23.8	nd	nd	nd	nd
4	2.6 ± 1.0	55.9	nd	nd	6.4 ± 0.3	49.6

^aSee Table 2 for precise DNA sequences used. ND = Not determined (i.e., K_d values >20 μM). Mean +/– SD of two independent experiments.