title: The Klebsiella pneumoniae wabG gene: role in biosynthesis of the core lipopolysaccharide and virulence.
abstract: To determine the function of the wabG gene in the biosynthesis of the core lipopolysaccharide (LPS) of Klebsiella pneumoniae, we constructed wabG nonpolar mutants. Data obtained from the comparative chemical and structural analysis of LPS samples obtained from the wild type, the mutant strain, and the complemented mutant demonstrated that the wabG gene is involved in attachment to alpha-L-glycero-D-manno-heptopyranose II (L,D-HeppII) at the O-3 position of an alpha-D-galactopyranosyluronic acid (alpha-D-GalAp) residue. K. pneumoniae nonpolar wabG mutants were devoid of the cell-attached capsular polysaccharide but were still able to produce capsular polysaccharide. Similar results were obtained with K. pneumoniae nonpolar waaC and waaF mutants, which produce shorter LPS core molecules than do wabG mutants. Other outer core K. pneumoniae nonpolar mutants in the waa gene cluster were encapsulated. K. pneumoniae waaC, waaF, and wabG mutants were avirulent when tested in different animal models. Furthermore, these mutants were more sensitive to some hydrophobic compounds than the wild-type strains. All these characteristics were rescued by reintroduction of the waaC, waaF, and wabG genes from K. pneumoniae.
authors.affiliation: Departamento de Microbiología y Parasitología Sanitarias, División de Ciencias de la Salud, Facultad de Farmacia,Universidad de Barcelona, Barcelona, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Izquierdo
authors.forename: Núria
authors.initials: N
authors.lastname: Coderch
authors.forename: Nuria
authors.initials: N
authors.lastname: Piqué
authors.forename: Emiliano
authors.initials: E
authors.lastname: Bedini
authors.forename: Maria Michela
authors.initials: MM
authors.lastname: Corsaro
authors.forename: Susana
authors.initials: S
authors.lastname: Merino
authors.forename: Sandra
authors.initials: S
authors.lastname: Fresno
authors.forename: Juan M
authors.initials: JM
authors.lastname: Tomás
authors.forename: Miguel
authors.initials: M
authors.lastname: Regué
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005816:Genetic Complementation Test; D007710:Klebsiella Infections / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000235:genetics* / Q000378:metabolism* / Q000472:pathogenicity; D007928:Lethal Dose 50; D008070:Lipopolysaccharides / Q000096:biosynthesis* / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D009154:Mutation; D010641:Phenotype; D018410:Pneumonia, Bacterial / Q000382:microbiology; D051381:Rats; D014552:Urinary Tract Infections / Q000382:microbiology; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D008070:Lipopolysaccharides