Low-Energy Electron-Induced Damage in a Trinucleotide Containing 5-Bromouracil
The reaction of low-energy electrons (LEEs; 10 eV) with 5′-TpXpT-3′ (TXT), where X is uracil (U), thymine (T), and 5-bromouracil (5BrU), was examined by HPLC-UV analysis. The presence of 5BrU increased total damage by >50%. The radiation products of T5BrUT included TUT (40%), free U, T, 5BrU (23%...
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Published in | The journal of physical chemistry. B Vol. 115; no. 46; pp. 13668 - 13673 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
United States
American Chemical Society
24.11.2011
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Subjects | |
Online Access | Get full text |
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Summary: | The reaction of low-energy electrons (LEEs; 10 eV) with 5′-TpXpT-3′ (TXT), where X is uracil (U), thymine (T), and 5-bromouracil (5BrU), was examined by HPLC-UV analysis. The presence of 5BrU increased total damage by >50%. The radiation products of T5BrUT included TUT (40%), free U, T, 5BrU (23%), and fragments (13%). These products may be explained by initial capture of LEEs by the nucleobase to form a transient anion, followed by transfer of the electron within the molecule and cleavage of susceptible bonds by dissociative electron attachment (C–Br, C–N, or C–O bonds). In addition, these products may arise from the uracilyl-5-yl (U-5-yl) radicals that undergo H-atom abstraction from the sugar moiety. Interestingly, several products contained two sites of cleavage (U, pUT, and TUp). The formation of these products was linear with dose, and thus, they arise from the single-electron reactions. To explain these products, we propose that the reaction of LEEs (10 eV) involves the coupling of two dissociative processes in the same molecule (for example, dissociative excitation and dissociative electron attachment). The latter reactions may contribute to the formation of clustered damage, which is the most deleterious damage induced by ionizing radiation. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Université de Sherbrooke. Tel: 1-819-820-6868 ext. 12717 Université de Sherbrooke The Open University |
ISSN: | 1520-6106 1520-5207 1520-5207 |
DOI: | 10.1021/jp205194g |