title: Irradiation of DNA with 193 nm light yields formamidopyrimidine-DNA glycosylase(Fpg) protein-sensitive lesions.
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 phi ssh = [1.5 +/- 0.1] x 10(4), argon-saturated sample phi ssh = [0.9 +/- 0.1] x 10(4). Treatment of the irradiated DNA samples with Escherichia coli formamidopyrimidine-DNA glycosylase (Fpg) protein results in an approximate 20-fold increase in the yield of single strand break-age (air-saturated sample phi fpg = [33.1 +/- 3.1] x 10(-4), argon-saturated sample phi fpg = [23.8 +/- 2.6] x 10(-4). This result indicates that 193 nm light induces other modification(s) (most likely of the purine moieties) that are 20 times more abundant than prompt strand breakage within the DNA matrix.
authors.affiliation: MRC Radiation and Genome Stability Unit, Harwell, Oxfordshire, UK. t.melvin@har-rbu.mrc.ac.uk
authors.forename: T
authors.initials: T
authors.lastname: Melvin
authors.forename: S
authors.initials: S
authors.lastname: Cunniffe
authors.forename: D
authors.initials: D
authors.lastname: Papworth
authors.forename: T
authors.initials: T
authors.lastname: Roldan-Arjona
authors.forename: P
authors.initials: P
authors.lastname: O'Neill
mesh_terms: D018736:DNA Adducts; D004274:DNA, Recombinant / Q000528:radiation effects*; D043382:DNA-Formamidopyrimidine Glycosylase; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins; D009699:N-Glycosyl Hydrolases / Q000096:biosynthesis*; D014466:Ultraviolet Rays
chemical_list: D018736:DNA Adducts; D004274:DNA, Recombinant; D029968:Escherichia coli Proteins; D009699:N-Glycosyl Hydrolases; D043382:DNA-Formamidopyrimidine Glycosylase; C468610:DNA-formamidopyrimidine glycosylase, E coli