title: A new family of proteins related to the HEAT-like repeat DNA glycosylases with affinity for branched DNA structures.
abstract: The recently discovered HEAT-like repeat (HLR) DNA glycosylase superfamily is widely distributed in all domains of life. The present bioinformatics and phylogenetic analysis shows that HLR DNA glycosylase superfamily members in the genus Bacillus form three subfamilies: AlkC, AlkD and AlkF/AlkG. The crystal structure of AlkF shows structural similarity with the DNA glycosylases AlkC and AlkD, however neither AlkF nor AlkG display any DNA glycosylase activity. Instead, both proteins have affinity to branched DNA structures such as three-way and Holliday junctions. A unique β-hairpin in the AlkF/AlkG subfamily is most likely inserted into the DNA major groove, and could be a structural determinant regulating DNA substrate affinity. We conclude that AlkF and AlkG represent a new family of HLR proteins with affinity for branched DNA structures.
authors.affiliation: Department of Microbiology, Oslo University Hospital and University of Oslo, P.O. Box 4950 Nydalen, 0424 Oslo, Norway.
authors.forename: Paul H
authors.initials: PH
authors.lastname: Backe
authors.forename: Roger
authors.initials: R
authors.lastname: Simm
authors.forename: Jon K
authors.initials: JK
authors.lastname: Laerdahl
authors.forename: Bjørn
authors.initials: B
authors.lastname: Dalhus
authors.forename: Annette
authors.initials: A
authors.lastname: Fagerlund
authors.forename: Ole A
authors.initials: OA
authors.lastname: Okstad
authors.forename: Torbjørn
authors.initials: T
authors.lastname: Rognes
authors.forename: Ingrun
authors.initials: I
authors.lastname: Alseth
authors.forename: Anne-Brit
authors.initials: AB
authors.lastname: Kolstø
authors.forename: Magnar
authors.initials: M
authors.lastname: Bjørås
mesh_terms: D001409:Bacillus cereus / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D002851:Chromatography, High Pressure Liquid; D016000:Cluster Analysis; D045647:DNA Glycosylases / Q000737:chemistry*; D004926:Escherichia coli / Q000235:genetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D017434:Protein Structure, Tertiary
chemical_list: D001426:Bacterial Proteins; D045647:DNA Glycosylases
keywords: AlkC; AlkD; Base excision repair; DNA damage; DNA glycosylases; Holliday junctions