MELTING PARAMETERS OF DNA COMPLEXES WITH SEVERAL INTERCALATORS

Comparative study of DNA complexes with acridine orange (AO), ethidium bromide (EtBr) and methylene blue (MB) has been carried out at 0.02 M ionic strength of solution in 0 < r ≤ 0.33, r = [ligand] / [DNA] range. The values of changes of melting parameters (δ(1/Tm) and δ(ΔT/Tm2)) of these complexes were determined. From the obtained data it was revealed that the dependence of δ(1/Tm) enhances in the whole interval of change of r for three ligands, while the dependence of δ(ΔT/Tm2) rises at relatively low values of r and comes out to plateau in the case of AO and MB; in the case of EtBr this dependence takes bell-like form.