Radiation damage in solid 5-halouracils: deoxyribose ring opening in single crystals of 5-chloro- and 5-bromodeoxyuridine

Journal Article · Sat Dec 01 04:00:00 EST 1979 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3574987· OSTI ID:5473960

Oloff, H ^[1]; Haindl, E; Huttermann, J; Krauss, J

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1. Univ., Regensburg, Germany

X irradiation of single crystals of 5-chlorodeoxyuridine (ClUdR) and 5-bromodeoxyuridine (BUdR) at 300/sup 0/K produces three different free-radical species which are isostructural in the two-crystal systems. One is the ..cap alpha..-halogen type RCHal(CH/sub 2/)R' described previously (1,2). Of the remaining free radicals, one has been analyzed in detail by ESR-ENDOR techniques. It exhibits a g-tensor with elements 2.0007, 2.0042, and 2.0065 and three hyperfine interactions, A (4.6 G, 6.6 G, 4.3 G), B (-4.8 G, -0.1 G, -5.1 G), and C (2.0 G, 0.7 G, 5.6 G). These spectral parameters are assigned to a free radical structure 0 = CH (C-OH)CHRR' at the O/sub 5'/C/sub 5'/C/sub 4'/C/sub 3'/ site of the deoxyribose group resulting from ring opening subsequent to fragmentation of a precursor alkoxy radical at the O/sub 5'/ locus. The third radical species is inaccessible to ESR studies but was found to give rise to a distinct ..cap alpha..-proton ENDOR-resonance line from which, as a tentative assignment, enolization of the C/sub 4/-pyrimidine base-located carbonyl function can be derived. These structures are discussed in relation to the radiosensitizing properties of 5-halouracils when replacing thymine residues in DNA.

• OSTI ID: 5473960
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 80:3; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

550200 -- Biochemistry
560111* -- Radiation Effects on Biochemicals-- In Vitro-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANTIMETABOLITES
ANTIMITOTIC DRUGS
AZINES
BIOCHEMICAL REACTION KINETICS
BROMOURACILS
BUDR
CHEMICAL RADIATION EFFECTS
CHEMISTRY
DEOXYURIDINE
DNA
DRUGS
ELECTROMAGNETIC RADIATION
ELECTRON SPIN RESONANCE
ENDOR
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
IONIZING RADIATIONS
KINETICS
MAGNETIC RESONANCE
MOLECULAR STRUCTURE
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC BROMINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIMIDINES
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RADICALS
RADIOSENSITIVITY
RADIOSENSITIVITY EFFECTS
REACTION KINETICS
RESONANCE
RIBOSIDES
THYMINE
URACILS
X RADIATION