title: Repair of O6-methylguanine by ABC excinuclease of Escherichia coli in vitro.
abstract: O6-Methylguanine, the major mutagenic product of methylnitroso compounds, was previously thought to be repaired exclusively by alkyltransferases I and II. Using synthetic substrates that contain O6-methyl-guanine at defined positions, we demonstrate that the nucleotide excision repair enzyme of Escherichia coli, ABC excinuclease, also repairs DNA containing this adduct. We show that the ABC excinuclease binds specifically to the modified DNA and produces incisions at the eight phosphodiester bond 5' and at the fifth or sixth phosphodiester bond 3' to the modified guanine.
authors.affiliation: Department of Pathology, University of North Carolina, Chapel Hill 27599.
authors.forename: J M
authors.initials: JM
authors.lastname: Voigt
authors.forename: B
authors.initials: B
authors.lastname: Van Houten
authors.forename: A
authors.initials: A
authors.lastname: Sancar
authors.forename: M D
authors.initials: MD
authors.lastname: Topal
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D001482:Base Composition; D004260:DNA Repair; D004269:DNA, Bacterial / Q000235:genetics*; D004706:Endodeoxyribonucleases / Q000378:metabolism / Q000502:physiology*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D006147:Guanine; C008449:O-(6)-methylguanine; D004706:Endodeoxyribonucleases; C036385:endodeoxyribonuclease uvrABC