Sensitized site-specific photomodification of ssDNA by binary systems of oligonucleotide conjugates. VI. Effect of substituents in the sensitizer anthracene residue

Photomodification of ssDNA by binary systems of oligonucleotide conjugates complementary to the adjacent sequences of the target DNA was studied. One of the conjugates comprised a substituted anthracene as a sensitizer; the o ther, p-azidotetrafluorobenzaldehyde 3-aminopropionylhydrazone as a photore agent. The sensitized photomodification is initiated by the 365-580-nm ligh t through an efficient energy transfer from the photoexcitated sensitizer o nto the photoreagent in a complementary complex of the binary system with t he DNA target where the sensitizer and the photoreagent are sterically conv erged. Influence of substituents in the anthracene residue on the efficienc y of the DNA sensitized photomodification was considered. The oligonucleoti de conjugate of anthracene-9al 3-aminopropionylhydrazone allows highly spec ific initiation of the sensitized photomodification upon irradiation with v isible light at >460 nm in conditions generating no photoreaction in the se nsitizer's absence.