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Vanadyl‐induced Fenton‐like reaction in RNA
Author(s) -
Carmichael Alasdair J.
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)80662-3
Subject(s) - chemistry , adduct , radical , spin trapping , electron paramagnetic resonance , hydrogen peroxide , photochemistry , hydroxyl radical , hydrolysis , rna , nitroxide mediated radical polymerization , medicinal chemistry , organic chemistry , polymerization , biochemistry , physics , nuclear magnetic resonance , gene , radical polymerization , polymer
Vanadyl (VO 2+ ) complexee to RNA reacts with hydrogen peroxide in a Fenton‐like manner producing hydroxyl radicals ('OH). The hydroxyl radicals can be spin trapped with 5,5‐dimethyl‐1‐pyrroline‐1‐oxide (DMPO) forming the DMPO‐OH spin adduct. In addition, in the presence of ethanol the formation of the hydroxyethyl radical adduct of DMPO (DMPO‐ETOH) confirms the production of hydroxyl radicals by the RNA/ VO 2+ complex. When the reaction between the RNA/VO 2+ complex and H 2 O 2 is carried out in the presence of the spin trap 2‐methyl‐2‐nitrosopropane (MNP), radicals produced in the reaction of . OH with RNA are trapped. Base hydrolysis of the MNP‐RNA adducts (pH 12) followed by a reduction in the pH to pH 7 after hydrolysis is complete, yields an MNP adduct with a well‐resolved ESR spectrum identical to the ESR spectrum obtained from analogous experiments with poly U. The ESR spectrum consists of a triplet of sextets ( a N = 1.48 mT, a N β = 0.25 mT and a H β = 0.14 mT), indicating that the unpaired nitroxide electron interacts with the nuclei of a β‐nitrogen and β‐hydrogen. The results suggest that the . OH generated in the RNA/VO 2+ reaction with H 2 O 2 add to the C(5) carbon of uracil forming a C(6) carbon centered radical. This radical is subsequently spin trapped by MNP.