Biopolymers and cell. 1997; 13 (1): 22 - 29

Investigation of phenazine derivatives interaction with DNA by polarized fluorescence method

Yu. P. Blagoi, V. N. Zozulya, I. M. Voloshin, V. L. Makitruk, A. S. Shalamay, A. S. Shcherbakova

The interaction of six phenazine derivatives belonging to glycosides and quaternary salts with DNA was studied by fluorescence polarized and absorption methods. Fluorescence properties of free dyes and their complexes with DNA were investigated. It was shown that the main type of binding of phenazines with a neutral chromophore is the dye intercalation between base pairs of the DNA double helix. For cationic dyes besides the intercalation the cooperative electrostatic interaction with phosphate groups makes the essential contribution to the complex formation. This interaction is manifested at both tow (ft - 0.002) and at moderate (n - 0.1) ionic strengths because of high hydrophobic effects. The equations of McGhee and van Hippel which were modified to take into account coulombic repultion between charged molecules binded to DNA and were used for the binding process analysis. Such modification makes it possible to describe experimental binding isotherms.