Photophysics and Photochemistry of DNA and RNA Bases

When a biological chromophore is irradiated by UV light becomes prone to photochemical reactions with prospective damage to the living organism. When those chromphores belong to the DNA/RNA macromolecules, the photobiological damage may lead to mutagenesis and carcinogenesis, phenomena that, although helpful for evolutionary purposes, we usually want to avoid. The purine and pyrimidine DNA/RNA bases seem however to be specifically photostable, that is, to prevent damage by dispersing energy from the initially excited state by efficient relaxation procedures prior to photochemical reactions to take place. The paths and mechanisms for such phenomena to take place are still under detailed research, and modern methods of quantum chemistry help to elucidate them, in particular because efficient energy relaxation implies the presence of conical intersections and energy crossings between nearby potential energy surfaces which can be computed using quantum chemical methods. The studies are applied to DNA/RNA base monomers and dimers. Apart from studying relaxation paths, the mechanism of formation of reactive triplet states in DNA/RNA monomers and dimers are also studied in the present project, together with the energy and electron transfer processes taking place along the DNA chain. Future projects include the study of the DNA/protein interaction and other reactions involved in the genetic replication mechanisms in order to get, from simple models, a picture of the photochemistry of nucleic acids.

Group participants:

Manuela Merchán
Luis Serrano-Andrés
Remedios González-Luque
Teresa Climent
Daniel Roca-Sanjuán
Israel González

Cooperation:

Luis Blancafort
Institut de Química Computacional
Universitat de Girona, Spain
http://www.udg.es

Mar Reguero y Elena Rodríguez
Departamento de Química Física y Química Inorgánica
Universitat Rovira i Virgili de Tarragona, Spain
http://www.urv.es

Daniel Monleón
Departamento de Química Física
Universidad de Málaga, Spain
http://www.uma.es

Mike A. Robb
Imperial College
University of London, UK
http://www.udg.es

Publications:

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