title: Three-dimensional structure of a DNA repair enzyme, 3-methyladenine DNA glycosylase II, from Escherichia coli.
abstract: The three-dimensional structure of Escherichia coli 3-methyladenine DNA glycosylase II, which removes numerous alkylated bases from DNA, was solved at 2.3 A resolution. The enzyme consists of three domains: one alpha + beta fold domain with a similarity to one-half of the eukaryotic TATA box-binding protein, and two all alpha-helical domains similar to those of Escherichia coli endonuclease III with combined N-glycosylase/abasic lyase activity. Mutagenesis and model-building studies suggest that the active site is located in a cleft between the two helical domains and that the enzyme flips the target base out of the DNA duplex into the active-site cleft. The structure of the active site implies broad substrate specificity and simple N-glycosylase activity.
authors.affiliation: Faculty of Pharmaceutical Sciences, Osaka University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yamagata
authors.forename: M
authors.initials: M
authors.lastname: Kato
authors.forename: K
authors.initials: K
authors.lastname: Odawara
authors.forename: Y
authors.initials: Y
authors.lastname: Tokuno
authors.forename: Y
authors.initials: Y
authors.lastname: Nakashima
authors.forename: N
authors.initials: N
authors.lastname: Matsushima
authors.forename: K
authors.initials: K
authors.lastname: Yasumura
authors.forename: K
authors.initials: K
authors.lastname: Tomita
authors.forename: K
authors.initials: K
authors.lastname: Ihara
authors.forename: Y
authors.initials: Y
authors.lastname: Fujii
authors.forename: Y
authors.initials: Y
authors.lastname: Nakabeppu
authors.forename: M
authors.initials: M
authors.lastname: Sekiguchi
authors.forename: S
authors.initials: S
authors.lastname: Fujii
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D003461:Crystallography; D045647:DNA Glycosylases; D004260:DNA Repair / Q000502:physiology*; D004269:DNA, Bacterial / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000737:chemistry; D004926:Escherichia coli / Q000737:chemistry / Q000201:enzymology*; D008969:Molecular Sequence Data; D009699:N-Glycosyl Hydrolases / Q000737:chemistry*; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D016385:TATA Box / Q000502:physiology
chemical_list: D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; C076131:DNA-3-methyladenine glycosidase II