Table 1. Equilibrium and kinetic constants for the interaction of compounds 1 and 3 with different sequence DNAs by SPR analysis^a.

	Keqb (×10–7)	kac (×10–5)	kdc (×103)	ka / kd (×10–7)
1-AATT	9.4	0.61	1.7	3.6
1-AT	6.3	1.1	1.3	8.1
1-GC	<1
3-AATT	2.1	3.0	12	2.6
3-AT	2.0	3.4	5.1	6.6
3-GC	0.18	0.47	25	0.20

We estimate the errors in BIA equilibrium constants for the single binding sites in this study to be: (i) for K values between ∼1 × 10⁵ and ∼2–3 × 10⁷, which is the most accurate range, errors are <10%; (ii) for K values between ∼5 × 10³ and ∼5 × 10⁴ errors increase to ∼15–20% due to the difficulty of reaching RU values close to the site saturation point; (iii) for K values >2–3 × 10⁷ errors again increase, due to the difficulty of collecting data at low amounts of site saturation. We estimate the error in the AT binding constants for compound 1 to be ∼10–15% and for compound 3 to be ∼10%. The error in the K for GC binding of compound 3 is ∼10–15%. These error estimates are in agreement with K values from repeat BIAcore experiments.

^aExperiments were conducted in HBS buffer at 25°C.

^bEquilibrium constants were determined from the RU values in the steady-state region of the sensorgrams at each concentration as described in the Materials and Methods.

^cKinetic constants were determined by global fitting of sensorgrams at all concentrations in each experiment.