Investigation of the pathways of excess electron transfer in DNA with flavin-donor and oxetane-acceptor modified DNA hairpins.
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 A. Attempts to trap the moving electron with N2O 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.
Breeger
Sascha
S
Department of Chemistry and Biochemistry, Ludwig-Maximilians-University Munich, Butenandtstrasse 5-13, Haus F, 81377 Munich, Germany.
von Meltzer
Martin
M
Hennecke
Ulrich
U
Carell
Thomas
T
D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D004247:DNA / Q000138:chemical synthesis / Q000737:chemistry*; D004260:DNA Repair; D004583:Electrons; D004988:Ethers, Cyclic / Q000138:chemical synthesis / Q000737:chemistry*; D005415:Flavins / Q000138:chemical synthesis / Q000737:chemistry*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation
D004988:Ethers, Cyclic; D005415:Flavins; D004247:DNA; C005287:oxetane