Features of the interaction of 5-[4′-(6"-aminopurin-2"-yl) phenyl]-10,15,20-tri(N-methylpyridin-3′-yl)-porphyrin with nucleic acids

Directed synthesis of novel water-soluble asymmetric porphyrins containing in a molecule three cationic fragments and residues of adenine (PorAD) was performed, using metal-complex catalysis method. The interaction of the synthesized porphyrin with the oligonucleotides poly[d(AT)2] and poly[d(GC)2] and double-stranded deoxyribonucleic acid of the calf thymus (ctDNA) was studied by means of spectral and hydrodynamic methods. It was established that PorAD intercalated not only into GC-enriched regions, but also into AT regions. It was revealed that a distinctive feature of PorAD complexes with nucleic acids was a weak shielding from water molecules, and it implies significant disturbances in the conformation of the nucleic acid; the disturbances being especially pronounced for poly[d(AT)2].