Adenine radiation damage

The examples of hydroxyl radical addition products identified in single crystals of adenine and guanine base derivatives confirm that water can play an important role in the radiation damage mechanism. It should be noted that the new mechanism has attracted some criticism [38]. The main objection is that nonplanar geometries were calculated for the gas phase radicals whereas planar structures are expected experimentally due to the hydrogen-bonding scheme... 

Raleigh JA, Blackburn BJ (1978) Substrate conformation in 5 -AMP-utilizing enzymes 8,5 -cyclo-adenosine 5 -monophosphate. Biochem Biophys Res Commun 83 1061-1066 Raleigh JA, Fuciarelli AF (1985) Distribution of damage in irradiated 5 -AMP 8,5 -cyclo-AMP, 8-hy-droxy-AMP, and adenine release. Radiat Res 102 165-175 Raleigh JA, Whitehouse R, Kremers W (1974) Effect of oxygen and nitroaromatic cell radiosensitizers on radiation-induced phosphate release from 3 - and 5 -nucleotides A model for nucleic adds. Radiat Res 59 453-465... 

Signorini N, Molko D, Cadet J (1998) Polyclonal antibodies to adenine N -oxide characterization and use for the measurement of DNA damage. Chem Res Toxicol 11 1169-1175 Simic M, Hayon E (1971) Radical reactions of N-ethyl maleimide in radiation sensitization. Int J Radiat Biol 20 589-592... 

Another common type of DNA damage is due to the formation of thymine dimers induced by ultraviolet and ionizing radiation. These intrastrand covalent bonds form a cyclobutyl ring between the C-5 and C-6 of one thymine, and the same carbons on the adjacent thymine. The result is that the DNA backbone on the thymine-containing strand is structurally altered, which may cause disruption of the hydrogen bonds with the corresponding adenine residues on the complementary strand (Fig. 23.2.). 

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