[Chemical ligation and recombination of DNA fragments by formation (exchange) of disulfide bonds, located in the sugar-phosphate backbone]. / Khimicheskoe ligirovanie i rekombinatsiia fragmentov DNK posredstvom obrazovaniia (obmena) disul'fidnykh sviazei, lokalizovannykh v sakharofosfatnom ostove.

ABSTRACT

Effective methods of the directed introduction of diphosphoryl disulfide bridges into hairpin DNA duplexes in place of natural phosphodiester groups were developed using the H2O2-effected ligation of 3'- and 5'-thiophosphorylated oligonucleotides or the autoligation of a preactivated oligonucleotide derivative with a phosphorothioate-bearing oligomer. The postsynthetic recombination of the disulfide-linked oligonucleotide fragments was characterized. It was shown that, along with template-directed reactions, out-of-duplex formation and exchange of diphosphoryl disulfide bonds in the DNA sugar-phosphate backbone may occur. In modified hairpin DNA, a spontaneous exchange of disulfide-linked fragments virtually does not take place because of the intramolecular duplex formation.