engleski

Interactions of phenanthridinium-nucleobase conjugates with complementary and non complementary polynucleotides in aqueous media

Interactions of a number of intercalator – nucleobase conjugates with targeted polynucleotides were recently intensively studied. We have investigated interactions of a novel class of phenanthridinium-nucleobase conjugates (Figure 1.) with complementary and non-complementary polynucleotides in aqueous media. Addition of polynucleotides to aqueous solution of phenanthridinium-nucleobase conjugates 1-3 showed significant changes in their fluorescence emission and UV/Vis spectra. Fluorimetric titrations indicate that phenanthridinium-nucleobase conjugates 1-3 form non-covalent complexes with polynucleotides in aqueous solutions. The stechiometry of the complexes was 1:1. UV/Vis and fluorimetric experiments were performed at pH = 7 and pH = 5 to compare results with those of studied phenanthridinium- nucleobase conjugates. Binding constants differ on the pH of the solution and were in ranges: from 103 – 102 dm3 mol-1 (pH = 7) and less than Ks <103 (pH = 5) for poly U and from 105 – 104 dm3 mol-1 (pH = 5 and 7) for poly A. No significant preferential binding was observed for conjugates with complementary polynucleotides (2 and 3). Aromatic  - stacking interactions are found to be dominant in complexes of all studied conjugates with polynucleotides.

phenanthridinium-nucleobase conjugates ; polynucleotides

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