title: Structural analysis of lipopolysaccharide produced by Heddleston serovars 10, 11, 12 and 15 and the identification of a new Pasteurella multocida lipopolysaccharide outer core biosynthesis locus, L6.
abstract: Pasteurella multocida is a Gram-negative bacterial pathogen classified into 16 serovars based on lipopolysaccharide (LPS) antigens. Previously, we have characterized the LPS outer core biosynthesis loci L1, L2, L3, L5 and L7, and have elucidated the full range of LPS structures associated with each. In this study, we have determined the LPS structures produced by the type strains representing the serovars 10, 11, 12 and 15 and characterized a new LPS outer core biosynthesis locus, L6, common to all. The L6 outer core biosynthesis locus shares significant synteny with the L3 locus but due to nucleotide divergence, gene duplication and gene redundancy, the L6 and L3 LPS outer cores are structurally distinct. Using LPS structural and genetic differences identified in each L6 strain, we have predicted a role for most of the L6 glycosyltransferases in LPS assembly. Importantly, we have identified two glycosyltransferases, GctD and GatB, that differ by one amino acid, A162T, but use different donor sugars [uridine diphosphate (UDP)-Glc and UDP-Gal, respectively]. The longest outer core oligosaccharide, produced by the serovar 12 type strain, contained a terminal region consisting of β-Gal-(1,4)-β-GlcNAc-(1,3)-β-Gal-(1,4)-β-Glc that was identical in structure to the vertebrate glycosphingolipid, paragloboside. Mimicry of host glycosphingolipids has been observed previously in P. multocida strains belonging to L3 LPS genotype, which produce LPS similar in structure to the globo-series of glycosphingolipids. The expression of a paragloboside-like oligosaccharide on the LPS produced by the serovar 12 type strain indicates that strains belonging to the L6 LPS genotype may also engage in molecular mimicry.
authors.affiliation: Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, VIC 3800, Australia marina.harper@monash.edu.
authors.forename: Marina
authors.initials: M
authors.lastname: Harper
authors.affiliation: Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, ON, Canada K1A 0R6.
authors.forename: Frank
authors.initials: F
authors.lastname: St Michael
authors.affiliation: Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, VIC 3800, Australia.
authors.forename: Marietta
authors.initials: M
authors.lastname: John
authors.affiliation: Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, VIC 3800, Australia.
authors.forename: Jason
authors.initials: J
authors.lastname: Steen
authors.affiliation: Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, ON, Canada K1A 0R6.
authors.forename: Lieke
authors.initials: L
authors.lastname: van Dorsten
authors.affiliation: Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, ON, Canada K1A 0R6.
authors.forename: Henrietta
authors.initials: H
authors.lastname: Parnas
authors.affiliation: Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, ON, Canada K1A 0R6.
authors.forename: Evgeny
authors.initials: E
authors.lastname: Vinogradov
authors.affiliation: Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, VIC 3800, Australia.
authors.forename: Ben
authors.initials: B
authors.lastname: Adler
authors.affiliation: Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, ON, Canada K1A 0R6.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Cox
authors.affiliation: Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, VIC 3800, Australia Department of Microbiology, Monash University, Clayton, VIC 3800, Australia.
authors.forename: John D
authors.initials: JD
authors.lastname: Boyce
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002240:Carbohydrate Sequence; D020440:Gene Duplication; D056426:Genetic Loci; D016680:Genome, Bacterial; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D016979:Pasteurella multocida / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D065288:Serogroup
chemical_list: D001426:Bacterial Proteins; D008070:Lipopolysaccharides; D016695:Glycosyltransferases
keywords: LPS; Pasteurella multocida; core oligosaccharide; genetics; structure