title: Investigation of the structural requirements in the lipopolysaccharide core acceptor for ligation of O antigens in the genus Salmonella: WaaL "ligase" is not the sole determinant of acceptor specificity.
abstract: The ligation of O antigen polysaccharide to lipid A-core oligosaccharide is a late step in the formation of the complex glycolipid known as lipopolysaccharide. Although the process has been localized to the periplasmic face of the inner membrane, details of the ligation mechanism have not been resolved. To date, there is only one gene product (WaaL, often referred to as "ligase") known to be required. There exists a requirement for a specific lipid A-core oligosaccharide acceptor structure for ligation activity, and it has been proposed that the WaaL protein imparts this acceptor specificity. Here the structural requirements in the core oligosaccharide acceptor for O antigen ligation are investigated in prototype serovars of Salmonella enterica. Complementation experiments in mutants with defined core oligosaccharide structure indicate that the specificity of the ligation reaction for a particular core oligosaccharide structure is not dependent on the WaaL protein alone. The data provide the first indication of a more complicated recognition process involving additional cellular components.
authors.affiliation: Department of Microbiology, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
authors.forename: Natalia A
authors.initials: NA
authors.lastname: Kaniuk
authors.forename: Evgeny
authors.initials: E
authors.lastname: Vinogradov
authors.forename: Chris
authors.initials: C
authors.lastname: Whitfield
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D015153:Blotting, Western; D002240:Carbohydrate Sequence; D019729:Carbon-Oxygen Ligases / Q000737:chemistry* / Q000502:physiology; D002455:Cell Division; D004247:DNA / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D005816:Genetic Complementation Test; D008055:Lipids / Q000737:chemistry; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D019081:O Antigens / Q000737:chemistry*; D019897:Periplasm / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D012475:Salmonella / Q000378:metabolism*; D019779:Salmonella enterica / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D016622:Silver Staining
chemical_list: D001426:Bacterial Proteins; D008055:Lipids; D008070:Lipopolysaccharides; D019081:O Antigens; D004247:DNA; D019729:Carbon-Oxygen Ligases; C491426:WaaL protein, Salmonella