Document Type
Article
Publication Date
7-17-2020
Abstract
Notwithstanding the central biological role of the (6-4) photoadduct in the induction of skin cancer by sunlight, crucial mechanistic details about its formation have evaded characterization despite efforts spanning more than half a century. 4-Thiothymidine (4tT) has been widely used as an important model system to study its mechanism of formation, but the excited-state precursor, the intermediate species, and the time scale leading to the formation of the (6-4) photoadduct have remained elusive. Herein, steady-state and time-resolved spectroscopic techniques are combined with new and reported quantum-chemical calculations to demonstrate the excited state leading to the formation of the thietane intermediate, its rate, and the formation of the (6-4) photoadduct using the 5’-TT(4tT)T(4tT)TT-3’ DNA oligonucleotide. Efficient, sub-1 ps intersystem crossing leads to the population of a triplet minimum of the thietane intermediate in as short as 3 ps, which intersystem crosses to its ground state and rearranges to form the (6-4) photoadduct.
Keywords
chemistry, excited states, photobiology
Language
English
Publication Title
Nature Communications
Grant
1800052
Rights
© The Author(s) 2020. This is an Open Access work distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Ortiz-Rodríguez, L.A., Reichardt, C., Hoehn, S.J. et al. Detection of the thietane precursor in the UVA formation of the DNA 6-4 photoadduct. Nat Commun 11, 3599 (2020). https://doi.org/10.1038/s41467-020-17333-y
Manuscript Version
Final Publisher Version