[Chemical synthesis and properties of oligonucleotide substrates for restriction endonuclease BamHI and methyltransferase Eco dam].

Oligodeoxyribonucleotides which form a number of duplexes, containing the recognition sequences for endonuclease BamHI and DNA methylase Eco dam, were synthesised by the phosphotriester approach. Furthermore, synthesis of 3'-phosphorylated oligodeoxyribonucleotides from corresponding S-methyl phosphorothioate triester oligomers is described. The synthetic duplexes are characterized by some defects in the recognition sequences for endonuclease BamHI and methylase Eco dam, viz. nick, absence of an internucleotide phosphate, modifications (including partial single-strandedness) of the recognition site. Interaction of the enzymes with these synthetic substrates was investigated.