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 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 a) J. Lhomme et al, Biochemistry, 1999, 38, 1930-7 ; b) J. Lhomme et al, Biochemistry, 1997, 36, 4831-43., Wilson WD et al, New J. Chem. 1994 ; 18, 419-423 ; Takenaka S et al, J. Chem. Soc., Chem. Commun. 1996 ; 379-380, Kubat P et al, J. Chem. Soc., Perkin Trans.1, 2000, 933-941. L.-M. Tumir, I. Piantanida, P. Novak, M. Žinić, J. Phys. Org. Chem, 2002, in press, I. Juranović et al, J. Chem. Soc., Chem. Commun., 2002, submitted.

intercalator - nucleobase conjugates; polynucleotides; fluorescence

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