Fig. 5. DNA melting experiment: the absorbance of the sample was monitored at 260 nm from 2 to 80 °C with a heating rate of 1 °C min−1. Conditions: dsDNA (5′-d(CTAACGGAATG)-3′/3′-d(GATTGGCTTAC)-5′, 5 μM) in phosphate buffer (10 mM, 100 mM NaCl, pH 7.0), in absence (black open circle) and presence of each ligand (compounds 2–4, 20 μM). (A) Compound 2; (B) 3; (C). 4. Ligands were either pretreated with heat at 60 °C in the dark to reach thermally equilibrated state (blue filled circle) or photo-irradiated at 365 nm for 20 s (red filled diamond). (D) Repeated irradiation of 3 with dsDNA. The sample before irradiation (cyan half-filled circle) was irradiated at 365 nm (red filled diamond), subsequent irradiation at 460 nm (blue filled circle), followed by irradiation at 365 nm (red half-filled diamond).
