title: Identification and characterization of a lipopolysaccharide α,2,3-sialyltransferase from the human pathogen Helicobacter bizzozeronii.
abstract: Terminal sialic acid in the lipopolysaccharides (LPSs) of mucosal pathogens is an important virulence factor. Here we report the characterization of a Helicobacter sialyltransferase involved in the biosynthesis of sialylated LPS in Helicobacter bizzozeronii, the only non-pylori gastric Helicobacter species isolated from humans thus far. Starting from the genome sequences of canine and human strains, we identified potential sialyltransferases downstream of three genes involved in the biosynthesis of N-acetylneuraminic acid. One of these candidates showed monofunctional α,2,3-sialyltransferase activity with a preference for N-acetyllactosamine as a substrate. The LPSs from different strains were shown by SDS-PAGE and high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) to contain sialic acid after neuraminidase treatment. The expression of this sialyltransferase and sialyl-LPS appeared to be a phase-variable characteristic common to both human and canine H. bizzozeronii strains. The sialylation site of the LPSs of two H. bizzozeronii strains was determined to be NeuAc-Hex-HexNAc, suggesting terminal 3'-sialyl-LacNAc. Moreover, serological typing revealed the possible presence of sialyl-Lewis X in two additional strains, indicating that H. bizzozeronii could also mimic the surface glycans of mammalian cells. The expression of sialyl-glycans may influence the adaptation process of H. bizzozeronii during the host jump from dogs to humans.
authors.affiliation: Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
authors.forename: Pradeep Kumar
authors.initials: PK
authors.lastname: Kondadi
authors.forename: Mirko
authors.initials: M
authors.lastname: Rossi
authors.forename: Brigitte
authors.initials: B
authors.lastname: Twelkmeyer
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: Schur
authors.forename: Jianjun
authors.initials: J
authors.lastname: Li
authors.forename: Thomas
authors.initials: T
authors.lastname: Schott
authors.forename: Lars
authors.initials: L
authors.lastname: Paulin
authors.forename: Petri
authors.initials: P
authors.lastname: Auvinen
authors.forename: Marja-Liisa
authors.initials: ML
authors.lastname: Hänninen
authors.forename: Elke K H
authors.initials: EK
authors.lastname: Schweda
authors.forename: Warren
authors.initials: W
authors.lastname: Wakarchuk
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial; D002772:Cholera Toxin; D004285:Dogs; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D016680:Genome, Bacterial; D016998:Helicobacter / Q000145:classification* / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008070:Lipopolysaccharides / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D011994:Recombinant Proteins; D012799:Sialyltransferases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000907:Antibodies, Bacterial; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D002772:Cholera Toxin; D012799:Sialyltransferases