title: Structural basis for the lack of opposite base specificity of Clostridium acetobutylicum 8-oxoguanine DNA glycosylase.
abstract: 7,8-Dihydro-8-oxoguanine (8-oxoG) is the major oxidative product of guanine and the most prevalent base lesion observed in DNA molecules. Because 8-oxoG has the capability to form a Hoogsteen pair with adenine (8-oxoG:A) in addition to a normal Watson-Crick pair with cytosine (8-oxoG:C), this lesion can lead to a G:C-->T:A transversion after replication. However, 8-oxoG is recognized and excised by the 8-oxoguanine DNA glycosylase (Ogg) of the base excision repair pathway. Members of the Ogg1 family usually display a strong preference for a C opposite the lesion. In contrast, the atypical Ogg1 from Clostridium actetobutylicum (CacOgg) can excise 8-oxoG when paired with either one of the four bases, albeit with a preference for C and A. Here we describe the first high-resolution crystal structures of CacOgg in complex with duplex DNA containing the 8-oxoG lesion paired to cytosine and to adenine. A structural comparison with human OGG1 provides a rationale for the lack of opposite base specificity displayed by the bacterial Ogg.
authors.affiliation: Department of Microbiology and Molecular Genetics, The Markey Center for Molecular Genetics, University of Vermont, Stafford Hall, 95 Carrigan Drive, Burlington, VT 05405-0068, USA.
authors.forename: Frédérick
authors.initials: F
authors.lastname: Faucher
authors.forename: Susan S
authors.initials: SS
authors.lastname: Wallace
authors.forename: Sylvie
authors.initials: S
authors.lastname: Doublié
mesh_terms: D001665:Binding Sites; D046969:Clostridium acetobutylicum / Q000201:enzymology*; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D045647:DNA Glycosylases / Q000737:chemistry* / Q000378:metabolism*; D006147:Guanine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D017434:Protein Structure, Tertiary; D040681:Structural Homology, Protein; D013379:Substrate Specificity
chemical_list: C024829:8-hydroxyguanine; D006147:Guanine; D004247:DNA; D045647:DNA Glycosylases