Yu Kay Law - DNA Excited-State Dynamics: From Single Bases to the Double Helix

Document created by Yu Kay Law on Aug 22, 2014
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  Publication Details (including relevant citation   information):

  Middleton, C. T., de La Harpe, K., Su, C., Law, Y. K.,   Crespo-Hernandez, C. E., and Kohler, B. (2009) DNA Excited-State   Dynamics: From Single Bases to the Double Helix, Annu. Rev. Phys.   Chem. 60, 217-239.


  Ultraviolet light is strongly absorbed by DNA, producing excited   electronic states that sometimes initiate damaging photochemical   reactions. Fully mapping the reactive and nonreactive decay   pathways available to excited electronic states in DNA is a   decades-old quest. Progress toward this goal has accelerated   rapidly in recent years, in large measure because of ultrafast   laser experiments. Here we review recent discoveries and   controversies concerning the nature and dynamics of excited   states in DNA model systems in solution. Nonradiative decay by   single, solvated nucleotides occurs primarily on the   subpicosecond timescale. Surprisingly, excess electronic energy   relaxes one or two orders of magnitude more slowly in DNA oligo-   and polynucleotides. Highly efficient nonradiative decay pathways   guarantee that most excited states do not lead to deleterious   reactions but instead relax back to the electronic ground state.   Understanding how the spatial organization of the bases controls   the relaxation of excess electronic energy in the double helix   and in alternative structures is currently one of the most   exciting challenges in the field.

  Address (URL): http://arjournals.annualreviews.org/doi/abs/10.1146/annurev.physchem.59.032607.0 93719