[DNA-like duplexes containing repetitive sequences. VII. Chemico-enzymatic synthesis of polymers with fragments of natural promotors].

Two types of DNA-duplexes containing the repeating fragments of natural promoters have been obtained starting from synthetic oligodeoxyribonucleotides TGCATTATAA, AACTAGTT, AGTTAACT. Deca- and octanucleotides have been synthesized by solid phase method with stepwise or blockwise chain elongation. UV- and CD-spectroscopy has been used to study the physico-chemical properties of the synthetic oligonucleotides. Polycondensation of oligonucleotides induced by water-soluble carbodiimide (chemical ligation) or T4-polynucleotide ligase allowed to synthesize the promoter models. The degree of polymerization varied from 2 to 8 in case of chemical ligation and from 2 to 30 in case of enzymatic ligation. A new chain length regulation technique has been developed by means of addition of a terminator of polycondensation (unphosphorylated oligonucleotide) in the reaction mixture.