Dynamics and Mechanism of DNA Repair in a Biomimetic System: Flavin鈥揟hymine Dimer Adduct

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• 作者：Ya-Ting Kao ; Qin-Hua Song ; Chaitanya Saxena ; Lijuan Wang ; Dongping Zhong
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：January 25, 2012
• 年：2012
• 卷：134
• 期：3
• 页码：1501-1503
• 全文大小：231K
• 年卷期：v.134,no.3(January 25, 2012)
• ISSN：1520-5126

文摘

To mimic photolyase for efficient repair of UV-damaged DNA, numerous biomimetic systems have been synthesized, but all show low repair efficiency. The molecular mechanism of this low-efficiency process is still poorly understood. Here we report our direct mapping of the repair processes of a flavin鈥搕hymine dimer adduct with femtosecond resolution. We followed the entire dynamic evolution and observed direct electron transfer (ET) from the excited flavin to the thymine dimer in 79 ps. We further observed two competitive pathways, productive dimer ring splitting within 435 ps and futile back-ET in 95 ps. Our observations reveal that the underlying mechanism for the low repair quantum yield of flavin鈥搕hymine dimer adducts is the short-lived excited flavin moiety and the fast dynamics of futile back-ET without repair.