Biopolymers and cell. 2000; 16 (1): 75 - 81

Interaction of cyanlne dyes with nucleic acids. 9. The study of spectral properties of cyanine dyes-DNA complexes in the presence of organic solvents

M. Yu. Losytskyy, V. B. Kovalska, S. M. Yarmoluk

The influence of medium polarity on spectral-luminescent properties of monomethyne cyanine dyes and their DNA-complexes has been studied in the presented work. The presence of organic solvent in aqueous dye and DNA-dye solutions resulted in significant decrease of DNA-dye complex fluorescence and increase of fluorescent intensity of free dyes. The fluorescence intensity of DNA-Ethidium bromide complexes depends weekly on the nature of the organic solvent. This result can be explained using the intercalary ion interaction model But for the cyanine dyes, have been studied, this dependence is much stronger. So, the considerable contact to the medium of the cyanine dyes bound to DNA has been shown to exist. Nevertheless, the interaction of these dyes with DNA showed no reference to the AT-sequences. So, in this presentation work we assume the studied cyanine dyes to interact with the DNA according to «half-intercalation» mechanism.