Showing papers by "Edwin E. Budzinski published in 1990"
TL;DR: The electrons trapped in single crystals of rhamnose X-irradiated at low temperature were studied by ENDOR spectroscopy and good agreement was obtained between experimental and calculated values.
Abstract: The electrons trapped in single crystals of rhamnose X-irradiated at low temperature were studied by ENDOR spectroscopy. Hyperfine couplings of protons in the environs of the electron have been determined from ENDOR measurements, including those of some of the more remote carbon-bound hydrogen atoms. The likely site of electron trapping in the crystal structure of rhamnose was inferred from calculations of the electric potential generated by the dipoles of hydroxy groups about preexisting void spaces. Electron-proton distances for nonexchangeable hydrogen atoms from points within the void were calculated from the crystal structure and compared with distances obtained from hyperfine couplings. Good agreement was obtained between experimental and calculated values.
19 citations
TL;DR: The radiation chemistry of the oligomer d(TpApCpG) X-irradiated in aqueous solution containing glutathione was studied and four products were isolated by HPLC and characterized by NMR spectroscopy, finding two of the major products are isomers of a 5-hydroxy-5,6-dihydrothymine modification of d( TpAp CpG).
Abstract: SummaryThe radiation chemistry of the oligomer d(TpApCpG) X-irradiated in aqueous solution containing glutathione was studied. Four products were isolated by HPLC and characterized by NMR spectroscopy. Two of the major products are isomers of a 5-hydroxy-5,6-dihydrothymine modification of d(TpApCpG). A dihydrothymine modification is also formed. The other major product is a result of strand scission. These products are different from the major products identified previously in a study of d(TpApCpG) X-irradiated in oxygenated solution. The effect of specific radiation-induced lesions on the behaviour of d(TpApCpG) as substrate to a spleen phosphodiesterase-micrococcal nuclease combination of enzymes and to nuclease P1 was studied. These enzymes are of interest because they are used in postlabelling assays of DNA damage.
13 citations
TL;DR: In this article, the coupling tensors for the hyperfine couplings between the electron and surrounding protons have been deduced from electron nuclear double resonance (ENDOR) data.
Abstract: Electrons are trapped at intermolecular sites in single crystals of sucrose X irradiated at 4.2 K. The coupling tensors for the hyperfine couplings between the electron and surrounding protons have been deduced from electron‐nuclear double resonance (ENDOR) data. Electron spin densities at nearby hydroxy protons are positive, whereas spin densities at the more remote protons of carbon‐bound hydrogen atoms are negative. The origin of these negative spin densities is discussed.
10 citations
TL;DR: Electrons are trapped in intermolecular voids in single crystals of dulcitol X-irradiated at low temperature and the hyperfine interactions between the trapped electron and the protons of the Hydroxy groups which form the trap suggest a highly symmetrical arrangement of two hydroxy groups in apposition.
Abstract: Electrons are trapped in intermolecular voids in single crystals of dulcitol X-irradiated at low temperature. The hyperfine interactions between the trapped electron and the protons of the hydroxy groups which form the trap suggest a highly symmetrical arrangement of two hydroxy groups in apposition. On the basis of this consideration the site in the crystal structure where trapping occurs was identified. In a parallel approach the crystal structure of dulcitol was surveyed for a suitable void encompassing a positive potential. The latter approach confirmed the same site in the crystal structure as the electron trapping site.
1 citations