Three-dimensional structure of a DNA repair enzyme, 3-methyladenine DNA glycosylase II, from Escherichia coli.
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.
Yamagata
Y
Y
Faculty of Pharmaceutical Sciences, Osaka University, Japan.
Kato
M
M
Odawara
K
K
Tokuno
Y
Y
Nakashima
Y
Y
Matsushima
N
N
Yasumura
K
K
Tomita
K
K
Ihara
K
K
Fujii
Y
Y
Nakabeppu
Y
Y
Sekiguchi
M
M
Fujii
S
S
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
D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; C076131:DNA-3-methyladenine glycosidase II