Publication
607
J. Phys. Chem. B , 110, 21987-21993, 2006.
DOI:
10.1021/jp062806c
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Electrochemical Approach to the Repair of Oxetanes Mimicking
DNA (6-4) Photoproducts |
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Fabien Boussicault and Marc Robert
Contribution from the Laboratoire d'Electrochimie Moléculaire, Université de Paris 7-Denis Diderot, 2 place Jussieu,75251 Paris Cedex 05, France
Electrochemical study of oxetanes mimicking DNA (6-4) photoproducts gives new
insight into the repair mechanism by (6-4) photolyase. Both electrochemical
oxidation and electrochemical reduction at carbon electrodes lead to the
cleavage of the oxetanes in a retro-Paterno-Büchi sequence. Within the family of
compounds investigated and the range of driving forces offered, transient
formation of unstable radical ions is observed, for both oxidative and reductive
cleavage. Taking advantage of the electrochemical signature of these mimics,
enzymatic assay with Escherichia coli CPD photolyase coupled to
electrochemical monitoring of the reaction brings evidence that enzymatic repair
of (6-4) DNA photoproducts does involve a catalytic dissociative
electron-transfer mechanism at the level of an oxetane intermediate. |