Pareamento de bases protege o DNA contra danos de raios ultravioletas

sábado, setembro 20, 2014

Watson–Crick Base Pairing Controls Excited-State Decay in Natural DNA†

Dominik B. Bucher1,2, Alexander Schlueter1, Prof. Dr. Thomas Carell2,* andProf. Dr. Wolfgang Zinth1,*
Article first published online: 4 SEP 2014

DOI: 10.1002/anie.201406286

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Angewandte Chemie International Edition
Early View (Online Version of Record published before inclusion in an issue)

+ We thank the Deutsche Forschungsgemeinschaft (SFB 749, TP A4 and A5, the Clusters of Excellence “Center for Integrated Protein Science Munich (CIPSM)” and “Munich-Center for Advanced Photonics” (MAP)) for financial support. The authors thank B. Kohler and W. Domcke for helpful discussions.

Source/Fonte: PhysOrg


base pairing;DNA photochemistry;excited-state decay;femtosecond IR spectroscopy;proton transfer


Excited-state dynamics are essential to understanding the formation of DNA lesions induced by UV light. By using femtosecond IR spectroscopy, it was possible to determine the lifetimes of the excited states of all four bases in the double-stranded environment of natural DNA. After UV excitation of the DNA duplex, we detected a concerted decay of base pairs connected by Watson–Crick hydrogen bonds. A comparison of single- and double-stranded DNA showed that the reactive charge-transfer states formed in the single strands are suppressed by base pairing in the duplex. The strong influence of the Watson–Crick hydrogen bonds indicates that proton transfer opens an efficient decay path in the duplex that prohibits the formation or reduces the lifetime of reactive charge-transfer states.


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