Interaction of UV Radiation with DNA Model Helices

Despite the high UV resistance of the DNA bases in solution, such light may still trigger photochemical reactions leading to carcinogenic mutations when it is absorbed by the double helix. Although the end products of these reactions are well characterized, the fundamental processes leading to their formation are not yet understood. Our recent work shows that;

  • a UV photon is not absorbed by individual bases but by collective states, delocalized over several bases (excitons)
  • energy transfer between different excitonic states takes place via intraband scattering in less than 100 fs
  • the organization of bases within the double helix can lead to a lowering of the ionization potential
  • the formation of (6-4) photo-adducts in a single strand (dT) 20 occurs within 4 ms and passes by a reaction intermediate

Publications and abstracts

#653 - Last update : 01/22 2009

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