title: The redefinition of Helicobacter pylori lipopolysaccharide O-antigen and core-oligosaccharide domains.
abstract: Helicobacter pylori lipopolysaccharide promotes chronic gastric colonisation through O-antigen host mimicry and resistance to mucosal antimicrobial peptides mediated primarily by modifications of the lipid A. The structural organisation of the core and O-antigen domains of H. pylori lipopolysaccharide remains unclear, as the O-antigen attachment site has still to be identified experimentally. Here, structural investigations of lipopolysaccharides purified from two wild-type strains and the O-antigen ligase mutant revealed that the H. pylori core-oligosaccharide domain is a short conserved hexasaccharide (Glc-Gal-DD-Hep-LD-Hep-LD-Hep-KDO) decorated with the O-antigen domain encompassing a conserved trisaccharide (-DD-Hep-Fuc-GlcNAc-) and variable glucan, heptan and Lewis antigens. Furthermore, the putative heptosyltransferase HP1284 was found to be required for the transfer of the third heptose residue to the core-oligosaccharide. Interestingly, mutation of HP1284 did not affect the ligation of the O-antigen and resulted in the attachment of the O-antigen onto an incomplete core-oligosaccharide missing the third heptose and the adjoining Glc-Gal residues. Mutants deficient in either HP1284 or O-antigen ligase displayed a moderate increase in susceptibility to polymyxin B but were unable to colonise the mouse gastric mucosa. Finally, mapping mutagenesis and colonisation data of previous studies onto the redefined organisation of H. pylori lipopolysaccharide revealed that only the conserved motifs were essential for colonisation. In conclusion, H. pylori lipopolysaccharide is missing the canonical inner and outer core organisation. Instead it displays a short core and a longer O-antigen encompassing residues previously assigned as the outer core domain. The redefinition of H. pylori lipopolysaccharide domains warrants future studies to dissect the role of each domain in host-pathogen interactions. Also enzymes involved in the assembly of the conserved core structure, such as HP1284, could be attractive targets for the design of new therapeutic agents for managing persistent H. pylori infection causing peptic ulcers and gastric cancer.
authors.affiliation: West China Marshall Research Center for Infectious Diseases, Center of Infectious Diseases, Division of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.|Helicobacter pylori Research Laboratory and Ondek Pty Ltd., School of Pathology & Laboratory Medicine, Marshall Centre for Infectious Disease Research and Training, University of Western Australia, Nedlands, Australia.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Life Sciences, Imperial College London, South Kensington Campus, London, United Kingdom.
authors.forename: Tiandi
authors.identifier: 0000-0002-6634-0847
authors.initials: T
authors.lastname: Yang
authors.affiliation: Helicobacter pylori Research Laboratory and Ondek Pty Ltd., School of Pathology & Laboratory Medicine, Marshall Centre for Infectious Disease Research and Training, University of Western Australia, Nedlands, Australia.
authors.forename: Tingting
authors.initials: T
authors.lastname: Liao
authors.affiliation: Helicobacter pylori Research Laboratory and Ondek Pty Ltd., School of Pathology & Laboratory Medicine, Marshall Centre for Infectious Disease Research and Training, University of Western Australia, Nedlands, Australia.|School of Chemistry and Biochemistry, University of Western Australia, Crawley, Australia.
authors.forename: Aleksandra W
authors.initials: AW
authors.lastname: Debowski
authors.affiliation: Helicobacter pylori Research Laboratory and Ondek Pty Ltd., School of Pathology & Laboratory Medicine, Marshall Centre for Infectious Disease Research and Training, University of Western Australia, Nedlands, Australia.
authors.forename: Hans-Olof
authors.initials: HO
authors.lastname: Nilsson
authors.affiliation: Helicobacter pylori Research Laboratory and Ondek Pty Ltd., School of Pathology & Laboratory Medicine, Marshall Centre for Infectious Disease Research and Training, University of Western Australia, Nedlands, Australia.
authors.forename: Alma
authors.initials: A
authors.lastname: Fulurija
authors.affiliation: Department of Life Sciences, Imperial College London, South Kensington Campus, London, United Kingdom.
authors.forename: Stuart M
authors.identifier: 0000-0002-5563-679X
authors.initials: SM
authors.lastname: Haslam
authors.affiliation: Department of Life Sciences, Imperial College London, South Kensington Campus, London, United Kingdom.
authors.forename: Barbara
authors.identifier: 0000-0003-3894-7622
authors.initials: B
authors.lastname: Mulloy
authors.affiliation: Department of Life Sciences, Imperial College London, South Kensington Campus, London, United Kingdom.
authors.forename: Anne
authors.initials: A
authors.lastname: Dell
authors.affiliation: School of Chemistry and Biochemistry, University of Western Australia, Crawley, Australia.
authors.forename: Keith A
authors.initials: KA
authors.lastname: Stubbs
authors.affiliation: Helicobacter pylori Research Laboratory and Ondek Pty Ltd., School of Pathology & Laboratory Medicine, Marshall Centre for Infectious Disease Research and Training, University of Western Australia, Nedlands, Australia.
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Marshall
authors.affiliation: Helicobacter pylori Research Laboratory and Ondek Pty Ltd., School of Pathology & Laboratory Medicine, Marshall Centre for Infectious Disease Research and Training, University of Western Australia, Nedlands, Australia.|Swiss Vitamin Institute, Route de la Corniche 1, Epalinges, Switzerland.
authors.forename: Mohammed
authors.identifier: 0000-0002-4207-0192
authors.initials: M
authors.lastname: Benghezal
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002849:Chromatography, Gas; D004195:Disease Models, Animal; D016481:Helicobacter Infections / Q000382:microbiology; D016480:Helicobacter pylori / Q000737:chemistry* / Q000472:pathogenicity*; D054884:Host-Pathogen Interactions / Q000502:physiology; D008070:Lipopolysaccharides / Q000737:chemistry*; D051379:Mice; D008810:Mice, Inbred C57BL; D019906:Nuclear Magnetic Resonance, Biomolecular; D019081:O Antigens / Q000737:chemistry*; D009844:Oligosaccharides / Q000737:chemistry; D000072417:Protein Domains; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D008070:Lipopolysaccharides; D019081:O Antigens; D009844:Oligosaccharides; C442865:lipopolysaccharide, Helicobacter pylori