title: Structure and mechanism of Staphylococcus aureus TarM, the wall teichoic acid α-glycosyltransferase.
abstract: Unique to Gram-positive bacteria, wall teichoic acids are anionic glycopolymers cross-stitched to a thick layer of peptidoglycan. The polyol phosphate subunits of these glycopolymers are decorated with GlcNAc sugars that are involved in phage binding, genetic exchange, host antibody response, resistance, and virulence. The search for the enzymes responsible for GlcNAcylation in Staphylococcus aureus has recently identified TarM and TarS with respective α- and β-(1-4) glycosyltransferase activities. The stereochemistry of the GlcNAc attachment is important in balancing biological processes, such that the interplay of TarM and TarS is likely important for bacterial pathogenicity and survival. Here we present the crystal structure of TarM in an unusual ternary-like complex consisting of a polymeric acceptor substrate analog, UDP from a hydrolyzed donor, and an α-glyceryl-GlcNAc product formed in situ. These structures support an internal nucleophilic substitution-like mechanism, lend new mechanistic insight into the glycosylation of glycopolymers, and reveal a trimerization domain with a likely role in acceptor substrate scaffolding.
authors.affiliation: Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, BC, Canada V6T 1Z3;
authors.forename: Solmaz
authors.initials: S
authors.lastname: Sobhanifar
authors.affiliation: Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, BC, Canada V6T 1Z3;
authors.forename: Liam James
authors.initials: LJ
authors.lastname: Worrall
authors.affiliation: Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, BC, Canada V6T 1Z3;
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Gruninger
authors.affiliation: Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, BC, Canada V6T 1Z3;
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Wasney
authors.affiliation: Department of Chemistry, University of British Columbia, Vancouver, BC, Canada V6T 1Z1; and.
authors.forename: Markus
authors.initials: M
authors.lastname: Blaukopf
authors.affiliation: Department of Chemistry, University of British Columbia, Vancouver, BC, Canada V6T 1Z1; and.
authors.forename: Lars
authors.initials: L
authors.lastname: Baumann
authors.affiliation: Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, BC, Canada V6T 1Z3;
authors.forename: Emilie
authors.initials: E
authors.lastname: Lameignere
authors.affiliation: Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, BC, Canada V6T 1Z3;
authors.forename: Matthew
authors.initials: M
authors.lastname: Solomonson
authors.affiliation: Department of Chemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada L8S 4K1.
authors.forename: Eric D
authors.initials: ED
authors.lastname: Brown
authors.affiliation: Department of Chemistry, University of British Columbia, Vancouver, BC, Canada V6T 1Z1; and.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Withers
authors.affiliation: Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, BC, Canada V6T 1Z3; ncjs@mail.ubc.ca.
authors.forename: Natalie C J
authors.initials: NC
authors.lastname: Strynadka
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000201:enzymology*; D003001:Cloning, Molecular; D003460:Crystallization; D004795:Enzyme Stability; D016695:Glycosyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013058:Mass Spectrometry; D008670:Metals / Q000032:analysis; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D058105:Polymerization; D011487:Protein Conformation; D013211:Staphylococcus aureus / Q000201:enzymology*; D013682:Teichoic Acids / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D008670:Metals; D013682:Teichoic Acids; D016695:Glycosyltransferases
keywords: bacterial pathogenicity; cell wall; crystal structure; glycosyltransferase; wall teichoic acid