UV-induced electron transfer between triethylamine and 5-bromo-2′-deoxyuridine. A puzzle concerning the photochemical debromination of labeled DNA

Paweł Wityk , Magdalena Zdrowowicz , Justyna Wiczk , Janusz Rak

Abstract

5-Bromo-2′-deoxyuridine (BrdU) photosensitizes DNA to strand break formation. However, this type of photodamage is completely quenched by the presence of triethylamine (TEA) which originates from RP-HPLC purification commonly employed by oligonucleotide providers. While the presence of TEA in oligonucleotide samples does not interfere with PCR or other molecular biology applications, the mechanism of photochemical reaction proceeding in the labeled DNA is dramatically changed due to the photoinduced electron transfer (PET) between the photoexcited BrdU and the ground state TEA. For the first time, we demonstrated that the latter process produces 2′-deoxyuridne2′-deoxyuridine (debromination) in the labeled DNA instead of the expected strand break. PET between TEA and BrdU was additionally confirmed by the UV irradiations of aqueous solutions containing both species. Indeed, the efficient formation of 2′-deoxyuridine was observed in the studied photolytes. Moreover, we showed the formation of an additional product in these binary mixtures, i.e. imidazole derivative, that is not formed in DNA and was reported in the literature in the context of dark rather than photochemical processes. Using mass spectrometry we demonstrated that the amount of TEA impurity in the commercial samples of oligos exceeds up to 3 orders of magnitude that of the purchased DNA.
Author Paweł Wityk PSB
Paweł Wityk,,
- Laboratory of Biological Sensitizers
, Magdalena Zdrowowicz PSB
Magdalena Zdrowowicz,,
- Laboratory of Biological Sensitizers
, Justyna Wiczk PSB
Justyna Wiczk ,,
- Laboratory of Biological Sensitizers
, Janusz Rak PSB
Janusz Rak,,
- Laboratory of Biological Sensitizers
Other language title versions
Journal seriesJournal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085
Issue year2017
Vol142
Pages262-269
Publication size in sheets0.5
Keywords in Englishtriethylamine, photoinduced electron transfer, synthetic oligonucleotides, mass spectrometry, debromination, strand break
DOIDOI:10.1016/j.jpba.2017.04.044
URL https://doi.org/10.1016/j.jpba.2017.04.044
Languageen angielski
Score (nominal)35
ScoreMinisterial score = 35.0, 20-12-2017, ArticleFromJournal
Ministerial score (2013-2016) = 35.0, 20-12-2017, ArticleFromJournal
Publication indicators WoS Impact Factor: 2016 = 3.255 (2) - 2016=2.953 (5)
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* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.
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