CATALYTIC CLEAVAGE OF TARGET DNA IN A COM PLEMENTARY COMPLEX WITH BLEOMYCIN DERIVATIVE OF OLIGONUCLEOTIDE

For the first time, reagents that are capable of catalytic site-specif ic cleavage of DNA were synthesized based on oligonucleotides. One mol ecule of reagent (Blm-R)pd(CCAAACA) containing bleomycin A(5) residue (Blm-RH) could degrade three molecules of target DNA pd(TGTTTGGCGAAGGA ). The reagent displayed maximum catalytic activity in a temperature r ange that was close to the melting temperature of the reagent-target D NA complex. The number of the target DNA molecules that could be degra ded by the reagent was limited by the degradation of the antibiotic re sidue itself during the oxidative degradation of the target DNA. The r eagent catalyzed the subsequent degradation of residues G(7), T-5, T-4 , and T-3 of the target DNA at an equimolar reagent-target DNA ratio. When the tenfold excess of the target DNA was used, the reagent degrad ed primarily the single G(7) residue of the target DNA by 30%.