title: Repair of helix-stabilizing anthramycin-N2 guanine DNA adducts by UVRA and UVRB proteins.
abstract: The transfectivity of anthramycin (Atm)-modified phi X174 replicative form (RF) DNA in Escherichia coli is lower in uvrA and uvrB mutant cells but much higher in uvrC mutant cells compared to wild-type cells. Pretreatment of the Atm-modified phage DNA with purified UVRA and UVRB significantly increases the transfectivity of the DNA in uvrA or uvrB mutant cells. This pretreatment greatly reduces the UVRABC nuclease-sensitive sites (UNSS) and Atm-induced absorbance at 343 nm in the Atm-modified DNA without producing apurinic sites. The reduction of UNSS is proportional to the concentrations of UVRA and UVRB and the enzyme-DNA incubation time and requires ATP. We conclude that there are two different mechanisms for repairing Atm-N2 guanine adducts by UVR proteins: (1) UVRA and UVRB bind to the Atm-N2 guanine double-stranded DNA region and consequently release the Atm from the adducted guanine; (2) UVRABC makes an incision at both sides of the Atm-DNA adduct. The latter mechanism produces potentially lethal double-strand DNA breaks in Atm-modified phi X174 RF DNA in vitro.
authors.affiliation: Science Park-Research Division University of Texas, M.D. Anderson Cancer Center, Smithville 78957.
authors.forename: M S
authors.initials: MS
authors.lastname: Tang
authors.forename: M E
authors.initials: ME
authors.lastname: Nazimiec
authors.forename: R P
authors.initials: RP
authors.lastname: Doisy
authors.forename: J R
authors.initials: JR
authors.lastname: Pierce
authors.forename: L H
authors.initials: LH
authors.lastname: Hurley
authors.forename: B E
authors.initials: BE
authors.lastname: Alderete
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000876:Anthramycin / Q000737:chemistry*; D001080:Apurinic Acid / Q000737:chemistry; D001426:Bacterial Proteins / Q000378:metabolism*; D004249:DNA Damage; D004265:DNA Helicases; D004260:DNA Repair; D004269:DNA, Bacterial / Q000737:chemistry; D004279:DNA, Viral / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004706:Endodeoxyribonucleases / Q000378:metabolism; D029968:Escherichia coli Proteins; D009154:Mutation; D013056:Spectrophotometry, Ultraviolet; D014162:Transfection
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C058093:UvrB protein, E coli; D000876:Anthramycin; D001080:Apurinic Acid; D004706:Endodeoxyribonucleases; C036385:endodeoxyribonuclease uvrABC; C068631:UvrA protein, E coli; D000251:Adenosine Triphosphatases; D004265:DNA Helicases