Primary reduction and oxidation of thymine derivatives. ESR/ENDOR of thymidine and 1-methylthymine x-irradiated at 10 K

Journal Article · Wed Feb 06 23:00:00 EST 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100156a086· OSTI ID:5160030

Hole, E O; Sagstuen, E ^[1]; Nelson, W H ^[2]; Close, D M ^[3]

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1. Univ. of Oslo (Norway)
2. Georgia State Univ., Atlanta (USA)
3. East Tennessee State Univ., Johnson City (USA)

Single crystals of thymidine and 1-methylthymine were x-irradiated at 10 K and studied by using K-band ESR, ENDOR, and FSE spectroscopy. In thymidine, six primary radicals were identified. The major species were the O4-protonated anion (TI), the radical formed by net H addition to the C6 position of the base (TII), the radical formed by net H abstraction from the methyl group (TIII), and the alkoxy radical (TVI). The two minority radicals were one formed by net H addition to the C5 position of the base (TIV) and one in which the unpaired spin was localized on the sugar moiety, thought to be a C1{prime} H abstraction radical (TV). A small, nonexchangeable coupling in radical TI was shown to be due to a coupling to the methyl group. Evidence is presented that the characteristics of this coupling tensor indicates the protonation state of the thymine anion radical. Upon annealing, the anion decayed at about 40 K with no detectable successor. The alkoxy radical decays in the same temperature range. In 1-methylthymine, three major radical species were identified.

• OSTI ID: 5160030
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:3; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600 -- Radiation Chemistry
560120* -- Radiation Effects on Biochemicals
Cells
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AZINES
CHEMICAL RADIATION EFFECTS
CRYSTALS
DATA
ELECTROMAGNETIC RADIATION
ELECTRON SPIN RESONANCE
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
IONIZING RADIATIONS
MAGNETIC RESONANCE
MEASURING METHODS
MONOCRYSTALS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIMIDINES
RADIATION EFFECTS
RADIATIONS
RESONANCE
RIBOSIDES
THYMIDINE
ULTRALOW TEMPERATURE
X RADIATION