1oe6
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XENOPUS SMUG1, AN ANTI-MUTATOR URACIL-DNA GLYCOSYLASE
OverviewOverview
Cytosine deamination is a major promutagenic process, generating G:U, mismatches that can cause transition mutations if not repaired. Uracil is, also introduced into DNA via nonmutagenic incorporation of dUTP during, replication. In bacteria, uracil is excised by uracil-DNA glycosylases, (UDG) related to E. coli UNG, and UNG homologs are found in mammals and, viruses. Ung knockout mice display no increase in mutation frequency due, to a second UDG activity, SMUG1, which is specialized for antimutational, uracil excision in mammalian cells. Remarkably, SMUG1 also excises the, oxidation-damage product 5-hydroxymethyluracil (HmU), but like UNG is, inactive against thymine (5-methyluracil), a chemical substructure of HmU., We have solved the crystal structure of SMUG1 complexed with DNA and, base-excision products. This structure indicates a more invasive, interaction with dsDNA than observed with other UDGs and reveals an, elegant water displacement/replacement mechanism that allows SMUG1 to, exclude thymine from its active site while accepting HmU.
About this StructureAbout this Structure
1OE6 is a Protein complex structure of sequences from Xenopus laevis with HMU, GOL and IPA as ligands. Structure known Active Site: AC1. Full crystallographic information is available from OCA.
ReferenceReference
Structure and specificity of the vertebrate anti-mutator uracil-DNA glycosylase SMUG1., Wibley JE, Waters TR, Haushalter K, Verdine GL, Pearl LH, Mol Cell. 2003 Jun;11(6):1647-59. PMID:12820976
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