Triplet-Induced Lesion Formation at CpT and TpC Sites in DNA.
Chemistry
; 25(66): 15164-15172, 2019 Nov 27.
Article
em En
| MEDLINE
| ID: mdl-31538684
ABSTRACT
UV irradiation induces DNA lesions particularly at dipyrimidine sites. Using time-resolved UV pump (250â
nm) and mid-IR probe spectroscopy the triplet pathway of cyclobutane pyrimidine dimer (CPD) formation within TpC and CpT sequences was studied. The triplet state is initially localized at the thymine base but decays with 30â
ns under formation of a biradical state extending over both bases of the dipyrimidine. Subsequently this state either decays back to the electronic ground state on the 100â
ns time scale or forms a cyclobutane pyrimidine dimer lesion (CPD). Stationary IR spectroscopy and triplet sensitization via 2'-methoxyacetophenone (2-M) in the UVA range shows that the lesions are formed with an efficiency of approximately 1.5 %. Deamination converts the cytosine moiety of the CPD lesions on the time scale of 10 hours into uracil which gives CPD(UpT) and CPD(TpU) lesions in which the coding potential of the initial cytosine base is vanished.
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01-internacional
Base de dados:
MEDLINE
Assunto principal:
Timina
/
DNA
/
Citosina
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article