Irradiation of DNA with 193 nm Light Yields Formamidopyrimidine-DNA Glycosylase (Fpg) Protein-Sensitive Lesions |
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Authors: | T Melvin S Cunniffe D Papworth T Roldan-Arjona P O'Neill |
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Institution: | MRC Radiation and Genome Stability Unit, Harwell, Oxfordshire, UK;ICRF, Clare Hall Laboratories, Blanche Lane, Potters Bar, UK |
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Abstract: | Abstract— Irradiation of aqueous solutions of plasmid DNA (pUC18) at pH 7.6 with 193 nm laser light results in low yields of prompt single strand breakage (air-saturated sample φssb= 1.5 ± 0.1] ± 10−4, argon-saturated sample φssb= 0.9 ± 0.1] ± 10−4). Treatment of the irradiated DNA samples with Escherichia coli formamidopyrimi-dine-DNA glycosylase (Fpg) protein results in an approximate 20-fold increase in the yield of single strand breakage (air-saturated sample φfpg= 33.1 ± 3.1] ± 10−4, argon-saturated sample φfpg= 23.8 ± 2.6] × 10 4). This result indicates that 193 nm light induces other modification) (most likely of the purine moieties) that are 20 times more abundant than prompt strand breakage within the DNA matrix. |
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