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Ultrafast Intersystem Crossing in Epigenetic DNA Nucleoside 2′-Deoxy-5-formylcytidine
- Source :
- The Journal of Physical Chemistry B. 123:5782-5790
- Publication Year :
- 2019
- Publisher :
- American Chemical Society (ACS), 2019.
-
Abstract
- DNA methylation and demethylation are the key steps in epigenetics. Emerging studies have demonstrated that these two processes play crucial roles in mammalian development and pathogenesis. Epigenetic modified cytosine and its further oxidative products, including 5-methylcytosine, 5-hydroxymethylcytosine, 5-formylcytosine, and 5-carboxylcytosine, are called the "new four bases of DNA". The appearance of such new epigenetic bases can complicate DNA photodamage and repairing mechanism because they could have drastically different excited-state dynamics compared to canonical DNA nucleobases. In this study, excited-state dynamics of three demethylated nucleosides in buffer solution at physiological pH were investigated by femtosecond to microsecond time-resolved spectroscopy. Distinct excited-state dynamics are found in these demethylated nucleosides. For 2'-deoxy-5-formylcytidine (5fdCyd), direct observation of ultrafast intersystem crossing to the triple state with a 69% quantum yield is presented. Meanwhile, the triplet-state energy of 5fdCyd can transfer to the ambient molecular oxygen and generate destructive singlet oxygen. On the other hand, no such observation is seen in 2'-deoxy-5-hydroxymethylcytidine (5hmdCyd) and 2'-deoxy-5-carboxycytidine (5cadCyd), and these two bases show ultrafast internal conversion similar to that in 5-methylcytidine and cytidine. These results indicate that 5fdCyd is an effective internal triplet photosensitizer in DNA, and it could act as a new hot spot in DNA photodamage.
- Subjects :
- Formylcytidine
010304 chemical physics
Chemistry
DNA
010402 general chemistry
Deoxyuridine
01 natural sciences
Epigenesis, Genetic
0104 chemical sciences
Surfaces, Coatings and Films
Cell biology
chemistry.chemical_compound
Intersystem crossing
0103 physical sciences
DNA methylation
Materials Chemistry
Nucleic Acid Conformation
Epigenetics
Physical and Theoretical Chemistry
Nucleoside
Demethylation
Subjects
Details
- ISSN :
- 15205207 and 15206106
- Volume :
- 123
- Database :
- OpenAIRE
- Journal :
- The Journal of Physical Chemistry B
- Accession number :
- edsair.doi.dedup.....b6e430bbaf5f035287a4bcf0b39431cb