title: Abasic site recognition mechanism by the Escherichia coli exonuclease III.
abstract: In order to elucidate the mechanism of AP site recognition by Echerichia coli exonuclease III (exoIII), site-directed mutagenesis of the Tyr109, the Trp212, and the Phe213 residues, which were conserved in the type II AP endonuclease from various organisms and located in the vicinity of the catalytic site, was performed. The exoIII-W212S mutant lacked any detectable AP endonuclease activity and binding ability to the duplex DNA containing an AP site, while the exoIII-Y109S and exoIII-F213W mutants retained a low level of activities (13% and 83%, respectively, compared with wild-type exoIII). This study suggests that the Trp212 is an important component for abasic site recognition by the E. coli exonuclease III.
authors.affiliation: Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Shida
authors.forename: K
authors.initials: K
authors.lastname: Kaneda
authors.forename: T
authors.initials: T
authors.lastname: Ogawa
authors.forename: J
authors.initials: J
authors.lastname: Sekiguchi
mesh_terms: D019943:Amino Acid Substitution; D001080:Apurinic Acid; D001483:Base Sequence; D001665:Binding Sites; D020134:Catalytic Domain; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000201:enzymology*; D005090:Exodeoxyribonucleases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D001080:Apurinic Acid; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III