Département de chimie moléculaire

Under irradn., Ru-TAP (TAP = 1,4,5,8-tetraazaphenanthrene) complexes tethered to oligonucleotides (Ru-ODN) hybridized to their complementary target sequences produce irreversible adducts with guanine (G) bases. The interesting feature is that the G bases that react in the double strand (DS) topol. belong exclusively to the complementary strand; thus, no G base of the Ru-ODN strand participates in the prodn. of these adducts. This highly specific photoreaction in the DS topol. is demonstrated by gel electrophoresis analyses of different duplex sequences in which the positions of the G bases are varied. Atomistic mol. modeling simulations indicate that this specificity is due to important steric constraints for the intrastrand adduct formation in the duplex. Luminescence lifetime measurements furnish more detailed information on these different duplex systems. [on SciFinder(R)]