ESR study of DNA base cation radicals produced by attack of oxidizing radicals
ESR investigations of ..gamma..-irradiated aqueous glasses (8 M NaClO/sub 4/, 12 M LiCl) containing DNA bases and analogues show that oxidizing species produced in the glasses (hydroxyl radicals and Cl/sub 2//sup -/) at 77 K attack a number of the bases and their analogues after warming to produce ..pi..-cation radicals. Compounds which produce ..pi.. cations include thymine, uracil, 3-methyluracil, 6-methyluracil, orotic acid, isoorotic acid, guanine, and adenine. Compounds which are not found to produce ..pi.. cations are 1-methylthymine, thymidine, and 1-methyluracil. The overall reaction for formation of the ..pi.. cations is as follows: base + OH.(Cl/sub 2//sup -/) ..-->.. OH/sup -/(2Cl/sup -/) + base cation. A pH and substituent dependence is also noted for the pyrimidines. At pHs where the nitrogen at position 1 is protonated, ..pi..-cation radicals are not formed. In addition, when there are substituents at position 1, ..pi.. cations are not found. Analysis of the ESR spectra of the DNA base ..pi.. cations for hyperfine splittings and g values were performed by aid of computer simulations. The analyses are in agreement with values found for several DNA base cations produced by photolysis and by direct ..gamma.. irradiation.
- Research Organization:
- Oakland Univ., Rochester, MI
- OSTI ID:
- 6507558
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 85:8; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400600* -- Radiation Chemistry
ADENINES
ALKALI METAL COMPOUNDS
AMINES
ANTIMETABOLITES
AQUEOUS SOLUTIONS
AZINES
CARBOXYLIC ACIDS
CHEMISTRY
CHLORIDES
CHLORINE
CHLORINE COMPOUNDS
DISPERSIONS
DNA
DRUGS
ELECTROMAGNETIC RADIATION
ELECTRON SPIN RESONANCE
ELEMENTS
GAMMA RADIATION
GLASS
GUANINE
HALIDES
HALOGEN COMPOUNDS
HALOGENS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
HYDROXYL RADICALS
IONIZING RADIATIONS
LITHIUM CHLORIDES
LITHIUM COMPOUNDS
LITHIUM HALIDES
LOW TEMPERATURE
MAGNETIC RESONANCE
MIXTURES
NONMETALS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OROTIC ACID
OXYGEN COMPOUNDS
PERCHLORATES
PURINES
PYRIMIDINES
RADIATION CHEMISTRY
RADIATIONS
RADICALS
RESONANCE
RIBOSIDES
SODIUM COMPOUNDS
SODIUM PERCHLORATES
SOLUTIONS
THYMIDINE
THYMINE
URACILS