Locating the uracil-5-yl radical formed upon photoirradiation of 5-bromouracil-substituted DNA.
In a previous study, we found that 2-deoxyribonolactone is effectively generated in the specific 5-bromouracil ((Br)U)-substituted sequence 5'-(G/C)[A]n = 1,2 (Br)U(Br)U-3' and proposed that a formed uracil-5-yl radical mainly abstracts the C1' hydrogen from the 5'-side of (Br)U(Br)U under 302-nm irradiation condition. In the present work, we performed photoirradiation of (Br)U-substituted DNA in the presence of a hydrogen donor, tetrahydrofuran, to quench the uracil-5-yl radical to uracil and then subjected the sample to uracil DNA glycosylase digestion. Slab gel sequence analysis indicated that uracil residues were formed at the hot-spot sequence of 5'-(G/C)[A]n = 1,2 (Br)U(Br)U-3' in 302-nm irradiation of (Br)U-substituted DNA. Furthermore, we found that the uracil residue was also formed at the reverse sequence 5'-(Br)U(Br)U[A]n = 1,2(G/C)-3', which suggests that both 5'-(G/C)[A]n = 1,2 (Br)U(Br)U-3' and 5'-(Br)U(Br)U[A]n = 1,2(G/C)-3' are hot-spot sequences for the formation of the uracil-5-yl radical.
Department of Chemistry, Graduate School of Science Kyoto University, Sakyo, Kyoto 606-8502, Japan.
Fumitaka
F
Hashiya
Department of Chemistry, Graduate School of Science Kyoto University, Sakyo, Kyoto 606-8502, Japan.
Abhijit
A
Saha
Department of Chemistry, Graduate School of Science Kyoto University, Sakyo, Kyoto 606-8502, Japan.
Seiichiro
S
Kizaki
Department of Chemistry, Graduate School of Science Kyoto University, Sakyo, Kyoto 606-8502, Japan.
Yue
Y
Li
Department of Chemistry, Graduate School of Science Kyoto University, Sakyo, Kyoto 606-8502, Japan Institute for Integrated Cell-Materials Science (iCeMS) Kyoto University, Sakyo, Kyoto 606-8502, Japan CREST, Japan Science and Technology Corporation (JST), Sanbancho, Chiyoda-ku, Tokyo 102-0075, Japan hs@kuchem.kyoto-u.ac.jp.
Hiroshi
H
Sugiyama
D001976:Bromouracil / Q000737:chemistry*; D004247:DNA / Q000737:chemistry* / Q000528:radiation effects; D004591:Electrophoresis, Polyacrylamide Gel; D005663:Furans / Q000737:chemistry; D017422:Sequence Analysis, DNA / Q000379:methods*; D014466:Ultraviolet Rays; D014498:Uracil / Q000737:chemistry*; D051981:Uracil-DNA Glycosidase
D005663:Furans; C018674:tetrahydrofuran; D001976:Bromouracil; D014498:Uracil; D004247:DNA; D051981:Uracil-DNA Glycosidase