[Photoactive ethidium and azidoethidium dyes. Synthesis, properties, and covalent bonding to oligodeoxynucleotides]

Methods of synthesis of ethidium and azidoethidium dyes, containing the primary aliphatic amino group of the 3-aminopropinoic acid residue were developed. The derivatives were characterized by spectral methods (NMR, UV- and fluorescent spectroscopy). Complex formation of ethidium dyes with DNA was studied by fluorescent technique. The stoichiometry of the dye--DNA complex was 1:4 (dye to base pair) for all the derivatives. Photoreactivity of azidoethidium dyes was 10(3) times higher and the quantum yield of the photoproducts was 10(5) times higher than those for ethidium dyes. A method of preparation of 5'-phosphoramide photoreactive oligodeoxynucleotide derivatives was suggested, with ethidium derivative of heptanucleotide pd(CCAAACA) as an example.