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. Author manuscript; available in PMC: 2013 May 2.
Published in final edited form as: Biochemistry. 2010 Jul 6;49(26):5540–5552. doi: 10.1021/bi100071j

Figure 2.

Figure 2

A graphical representation of thiazole orange displacement assay. (A) A raw emission data of 1.25 µM thiazole orange upon excitation at 534 nm with buffer only (open circles) and after addition of 0.88 µM/bt poly(dA)•2poly(dT) triplex (black circles). BQQ-neomycin was then titrated from 0.25 µM to 1.06 mM. (B) The decrease in the fluorescence intensity of the complex (DNA-thiazole orange) upon addition of BQQ-neomycin aliquots. (C) Assuming a linear relationship between the changes in fluorescence intensity with the fraction of thiazole orange displaced results in S-shaped binding isotherm. This graph allows the determination of concentration of ligands needed to displace half of the thiazole orange from the DNA triplex.

Buffer conditions: 150 mM KCl, 10 mM SC, 0.5 mM EDTA, pH 6.8. [poly(dA).2poly(dT)] = 0.88 µM/bt. [TO] = 1.25 µM