NEW APPROACH TO ENHANCING THE EFFICIENCY AND SPECIFICITY OF INTERACTION IN DUPLEXES BY THE USE OF TANDEM STRUCTURE

Examined in this work is ssDNA recognition by tetranucleotides and the ir alkylating derivatives in the presence of effecters (native oligonu cleotides and their derivatives bearing a duplex stabilizing group suc h as phenazinium). Though tetranucleotides themselves are not capable of interacting with DNA, the effective site specific DNA recognition b y tetranucleotides and their alkylating reagents is caused by the pres ence of flanking effector pair. The influence of diphenazinium octanuc leotide derivatives on the interaction of tetranucleotide or its react ive derivatives with DNA by far exceeds the influence of native octanu cleotides. The level of DNA modification by the alkylating moiety of t etranucleotide depends on hybribization properties of the effector. Te tranucleotide forms complexes with the same DNA-target site with T-m c hanging from 0 degrees C to 38 degrees C. Besides, the tetranucleotide reagent modifies that site. the extent of modification varies from 0% to 60%, depending on a type of the effecters used. Having itself seve ral binding sites, the tetranucleotide reagent is made to interact wit h DNA target exclusively in one binding site determined by the sequenc e of the flanking effector pair. A new method based on the usage of fl anking effector pairs is thus proposed for enhancing the efficiency an d specificity of DNA recognition by short oligonucleotides and for dis criminating their binding sites.