engleski

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

Interactions of a number of intercalator – nucleobase conjugates with targeted nucleotides were recently intensively studied [ ]. Among the others, some phenanthridinium – nucleobase conjugates have shown preferential binding toward complementary polynucleotides [ ]. In order to study possible additivity and consequently to achieve a higher selectivity we have prepared novel conjugates with the nucleobases linked to both sides of the phenanthridinium unit by a C3 methylene chain. Addition of nucleotides 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 nucleotides in aqueous solutions. The stoichiometry of the complexes was 1:1 and binding constants were in the range 102 – 101 dm3 mol-1. No significant preferential binding was observed for conjugates with complementary nucleotides (2 and 3). Aromatic p-p stacking interactions are found to be dominant in complexes of all studied conjugates with nucleotides

phenanthridinium – nucleobase conjugate; polynucleotides; fluorimetric titration

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