UV-Induced Proton-Coupled Electron Transfer in Cyclic DNA Miniduplexes.
J Am Chem Soc
; 138(23): 7395-401, 2016 06 15.
Article
em En
| MEDLINE
| ID: mdl-27203223
ABSTRACT
The excited-state dynamics of two cyclic DNA miniduplexes, each containing just two base pairs, are investigated using time-resolved infrared spectroscopy. As in longer DNA duplexes, intrastrand electron transfer induced by UV excitation triggers interstrand proton transfer in the alternating miniduplex containing two out-of-phase G·C base pairs. The resulting excited state decays on a time scale of several tens of picoseconds. This state is absent when one of the two G residues is substituted by 8-oxo-7,8-dihydroguanine, a modification that is suggested to disrupt base stacking, while maintaining base pairing. These findings demonstrate that a nucleobase tetramer arranged as two stacked base pairs accurately captures the interplay between intrastrand and interstrand decay channels. The similar signals seen in the miniduplexes and longer sequences suggest that excited states in the latter rapidly localize on two adjacent base pairs.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Prótons
/
Raios Ultravioleta
/
DNA
/
Pareamento de Bases
/
Transporte de Elétrons
/
Guanina
Idioma:
En
Revista:
J Am Chem Soc
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Estados Unidos