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Ring Opening of the Cyclobutane in a Thymine Dimer Radical Anion
Author(s) -
Chatgilialoglu Chryssostomos,
Guerra Maurizio,
Kaloudis Panagiotis,
HouéeLévin Chantal,
Marignier JeanLouis,
Swaminathan Vijay N.,
Carell Thomas
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200700807
Subject(s) - thymine , cyclobutane , pyrimidine dimer , radiolysis , chemistry , dimer , photochemistry , photolyase , one electron reduction , stereochemistry , dna , ring (chemistry) , radical , dna damage , dna repair , organic chemistry , biochemistry , electrode , electrochemistry
The reactions of hydrated electrons (e aq − ) with thymine dimer 2 and thymidine have been investigated by radiolytic methods coupled with product studies, and addressed computationally by means of BB1K‐HMDFT calculations. Pulse radiolysis revealed that one‐electron reduction of the thymine dimer 2 affords the radical anion of thymidine ( 5 ) with t 1/2 <35 ns. Indeed, the theoretical study suggests that radical anion 3 , in which the spin density and charge distribution are located in both thymine rings, undergoes a fast partially ionic splitting of the cyclobutane with a half‐life of a few ps. This model fits with the in vivo observation of thymine dimer repair in DNA by photolyase. γ‐Radiolysis of thymine dimer 2 demonstrates that the one‐electron reduction and the subsequent cleavage of the cyclobutane ring does not proceed by means of a radical chain mechanism, that is, in this model reaction the T −. is unable to transfer an electron to the thymine dimer 2 .