This research focuses on the distance of electron and `positive hole` migration in DNA. The working paradigm is is that photogenerated electrons and holes migrate from the site of initial generation to removed sites at which strand cleavage or oxidative damage occurs. Photoactive benzo(a)pyrene derivatives are covalently bound, site-specifically, to commercially available DNA fragments with a defined base sequence. Strand cleavage patterns within these defined systems will be established by high resolution gel electrophoresis, and correlated with the efficiencies of DNA strand cleavage and oxidative damage to assess electron-hole migration distances, and the sites within the biopolymer at which hole-initiated oxidative damage, and electron-initiated strand cleavage occur. Phototherapeutic and photosterilization applications have focused attention on the mechanism by which photoactive reagents oxidatively damage and/or cleave DNA duplexes. With this award, Professor Geacintov will elucidate the distances of charge migration in DNA fragments having a defined base sequence thereby identifying the sites at which strand cleavage and oxidative damage occur.
