title: Structure of a metal-independent bacterial glycosyltransferase that catalyzes the synthesis of histo-blood group A antigen.
abstract: Histo-blood group antigens (HBGAs) are a source of antigenic variation between individuals that modulates resistance and susceptibility to pathogens and is a barrier to the spread of enveloped viruses. HBGAs are also produced by a few prokaryotes where they are synthesized by glycosyltransferases (GTs) related to human HBGA synthases. Here we report the first structure of a bacterial GT of this family, from an intestinal resident, Bacteroides ovatus. Unlike its mammalian homologues and other GTs with similar folds, this protein lacks a metal-binding Asp-X-Asp motif and is fully active in the absence of divalent metal ions, yet is strikingly similar in structure and in its interactions with substrates to structurally characterized mammalian metal-dependent mammalian homologues. This shows how an apparently major divergence in catalytic properties can be accommodated by minor structural adjustments and illustrates the structural underpinnings of horizontal transfer of a functional gene from prokaryotes to vertebrates.
authors.affiliation: Department of Biology and Biochemistry, University of Bath , Claverton Down, Bath BA2 7AY,  UK.
authors.forename: Nethaji
authors.initials: N
authors.lastname: Thiyagarajan
authors.forename: Tram T K
authors.initials: TT
authors.lastname: Pham
authors.forename: Brittany
authors.initials: B
authors.lastname: Stinson
authors.forename: Amit
authors.initials: A
authors.lastname: Sundriyal
authors.forename: Percy
authors.initials: P
authors.lastname: Tumbale
authors.forename: Michelle
authors.initials: M
authors.lastname: Lizotte-Waniewski
authors.forename: Keith
authors.initials: K
authors.lastname: Brew
authors.forename: K Ravi
authors.initials: KR
authors.lastname: Acharya
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D001439:Bacteroides / Q000201:enzymology*; D001665:Binding Sites; D055162:Biocatalysis; D018360:Crystallography, X-Ray; D016695:Glycosyltransferases / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008670:Metals / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity; D013816:Thermodynamics
chemical_list: D000017:ABO Blood-Group System; D001426:Bacterial Proteins; D008670:Metals; D016695:Glycosyltransferases