Electron-induced dissociation of the potential radiosensitizer 5-selenocyanato-2′-deoxyuridine

Rebecca Meißner , Samanta Makurat , Witold Kozak , Paulo Limão-Vieira , Janusz Rak , Stephan Denifl

Abstract

5-Selenocyanato-2′-deoxyuridine (SeCNdU) is a recently proposed radiosensitizer based on 2′-deoxyuridine (dU) with the electron-affinic selenocyanato (−SeCN) side group attached at the C5 position of uracil. Since electron interaction processes may be an important source of DNA damage by ionizing radiation, we have studied low-energy dissociative electron attachment to SeCNdU in the gas phase. Negative ion formation has been obtained by means of mass spectrometry, where a rich fragmentation pattern is observed even at ∼0 eV. The reaction pathways exhibiting the highest ion yields are C4N2O2H2Se•− and CN−, both involving a cleavage of the Se−CN bond. The heaviest fragment anion observed is C9N2O5H10Se•−, where besides the charged species, the hydrogen and cyano radicals are also formed. Further decomposition channels also yield the highly reactive hydroxyl radical, which possesses a high DNA damage potential. All observed channels have experimentally determined onsets at 0 eV, which are supported by calculations performed at the M06-2X/aug-ccpVTZ level. The calculations comprise the thermochemical thresholds at standard and experimental (428.15 K, 3 × 10−11 atm) conditions together with the adiabatic electron affinities. The present study shows that low-energy electrons very effectively decompose SeCNdU upon attachment of thermal electrons, producing a large variety of charged fragments and radicals.
Author Rebecca Meißner
Rebecca Meißner,,
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, Samanta Makurat (FCh / DPCh / LBS)
Samanta Makurat,,
- Laboratory of Biological Sensitizers
, Witold Kozak (FCh / DPCh / LBS)
Witold Kozak,,
- Laboratory of Biological Sensitizers
, Paulo Limão-Vieira
Paulo Limão-Vieira,,
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, Janusz Rak (FCh / DPCh / LBS)
Janusz Rak,,
- Laboratory of Biological Sensitizers
, Stephan Denifl
Stephan Denifl,,
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Journal seriesJournal of Physical Chemistry B, ISSN 1520-6106, (N/A 100 pkt)
Issue year2019
Vol123
No6
Pages1274-1282
Publication size in sheets0.5
ASJC Classification2505 Materials Chemistry; 2508 Surfaces, Coatings and Films; 1606 Physical and Theoretical Chemistry
DOIDOI:10.1021/acs.jpcb.8b11523
URL https://pubs.acs.org/doi/10.1021/acs.jpcb.8b11523
Languageen angielski
Score (nominal)100
ScoreMinisterial score = 100.0, 30-09-2019, ArticleFromJournal
Publication indicators Scopus SNIP (Source Normalised Impact per Paper): 2017 = 1.015; WoS Impact Factor: 2017 = 3.146 (2) - 2017=3.101 (5)
Citation count*2 (2019-10-15)
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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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