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Investigation of the Pathways of Excess Electron Transfer in DNA with Flavin-Donor and Oxetane-Acceptor Modified DNA Hairpins

✍ Scribed by Sascha Breeger; Martin von Meltzer; Ulrich Hennecke; Thomas Carell


Publisher
John Wiley and Sons
Year
2006
Tongue
English
Weight
403 KB
Volume
12
Category
Article
ISSN
0947-6539

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✦ Synopsis


Abstract

Oxetane is a potential intermediate that is enzymatically formed during the repair of (6–4) DNA lesions by special repair enzymes (6–4 DNA photolyases). These enzymes use a reduced and deprotonated flavin to cleave the oxetane by single electron donation. Herein we report synthesis of DNA hairpin model compounds containing a flavin as the hairpin head and two different oxetanes in the stem structure of the hairpin. The data show that the electron moves through the duplex even over distances of 17 Å. Attempts to trap the moving electron with N~2~O showed no reduction of the cleavage efficiency showing that the electron moves through the duplex and not through solution. The electron transfer is sequence dependent. The efficiency is reduced by a factor of 2 in GC rich DNA hairpins.