Repair of a Dimeric Azetidine Related to the Thymine-Cytosine (6-4) Photoproduct by Electron Transfer Photoreduction
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- 作者：Ana B. Fraga-Timiraos ; Dr. Virginie Lhiaubet-Vallet and Prof. Miguel A. Miranda
- 刊名：Angewandte Chemie
- 出版年：2016
- 出版时间：May 10, 2016
- 年：2016
- 卷：128
- 期：20
- 页码：6141-6144
- 全文大小：1717K
- ISSN：1521-3757
文摘
Photolyases are intriguing enzymes that take advantage of sunlight to restore lesions like cyclobutane pyrimidine dimers or (6-4) photoproducts. This work focused on the photoreductive process responsible for splitting of the azetidine ring proposed to occur during (6-4) photoproduct repair at a thymine–cytosine sequence. A model compound formed by photocycloaddition between thymine and 6-azauracil has been designed to mimic the elusive azetidine intermediate. The photoinduced electron transfer process has been investigated by means of steady-state and time-resolved fluorescence using photosensitizers with oxidation potentials in the singlet excited state ranging from −3.3 to −2.1 V vs. SCE. Azetidine ring splitting and recovery of “repaired” bases were proven by HPLC analysis.