Effects of ionizing radiation in cocrystals of DNA model compounds: ESR-ENDOR studies of x-irradiated imidazole:barbital and adenosine:5-bromouracil
Electron spin resonance (ESR) and electron nuclear double resonance (ENDOR) techniques have been used to study radition induced damage in cocrystalline complexes. The study addresses the following questions: (1) whether radiation induced damage is stabilized preferentially on one of the components of the cocrystalline system; and (2) whether charge transfer occurs between purine and pyrimidine bases in hydrogen bonded or stacked configurations. The cocrystals used are imidazole: 5,5-diethylbarbituric acid (barbital) and adenosine: 5-bromouracil (AR:BU). The predominant free radicals trapped in single crystals of this complex X-irradiated at 12K are the barbital ..pi..-anion and the imidazole ..pi..-cation. Structural analysis of the imidazole ring relative to the crystal structure at 300K. The preferential stabilization of ..pi..-anions on barbital and ..pi..-cations on imidazole is explained by a selective electron capture model. The radiation chemistry of the AR:BU cocrystal at 12K shows that electron gain and electron loss products are stabilized on both A and BU. These results indicate that (1) preferential stabilization of radition damage may be observed in a cocrystal even in the absence of stacking interactions; (2) in the presence of purine:pyrimidine stacking electron transfer may occur, but hole transfer is not likely to be the mechanism of redistribution of radiation damage in cocrystalline systems. The radiation chemistry of AR:BU is used as a model to predict the effects of ionizing radiation on DNA. 22 figures, 8 tables.
- Research Organization:
- Rochester Univ., NY (USA). Dept. of Radiation Biology and Biophysics
- DOE Contract Number:
- AC02-76EV03490
- OSTI ID:
- 6876716
- Report Number(s):
- DOE/EV/03490-2015; ON: DE84016261
- Resource Relation:
- Other Information: Portions are illegible in microfiche products. Thesis
- Country of Publication:
- United States
- Language:
- English
Similar Records
Electron gain and electron loss radicals stabilized on the purine and pyrimidine of a cocrystal exhibiting base-base interstacking: ESR-ENDOR of X-irradiated adenosine:5-bromouracil
Imidazole. pi. cation and barbital. pi. anion trapped in a cocrystalline complex x-irradiated at 12 K: An ESR--ENDOR study
Related Subjects
COMPLEXES
CHEMICAL RADIATION EFFECTS
ADENOSINE
BARBITURATES
BROMOURACILS
CRYSTAL STRUCTURE
ELECTRON SPIN RESONANCE
EXPERIMENTAL DATA
IMIDAZOLES
ANESTHETICS
ANTIMETABOLITES
AZINES
AZOLES
CENTRAL NERVOUS SYSTEM DEPRESSANTS
CHEMISTRY
DATA
DRUGS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
HYPNOTICS AND SEDATIVES
INFORMATION
MAGNETIC RESONANCE
NUCLEOSIDES
NUCLEOTIDES
NUMERICAL DATA
ORGANIC BROMINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PYRIMIDINES
RADIATION CHEMISTRY
RADIATION EFFECTS
RESONANCE
RIBOSIDES
URACILS
400600* - Radiation Chemistry