title: The ionic interaction of Klebsiella pneumoniae K2 capsule and core lipopolysaccharide.
abstract: The complete structures of LPS core types 1 and 2 from Klebsiella pneumoniae have been described by other authors. They are characterized by a lack of phosphoryl residues, but they contain galacturonic acid (GalA) residues, which contribute to the necessary negative charges. The presence of a capsule was determined in core-LPS non-polar mutants from strains 52145 (O1 : K2), DL1 (O1 : K1) and C3 (O8 : K66). O-antigen ligase (waaL) mutants produced a capsule. Core mutants containing the GalA residues were capsulated, while those lacking the residues were non capsulated. Since the proteins involved in the transfer of GalA (WabG) and glucosamine residues (WabH) are known, the chemical basis of the capsular-K2-cell-surface association was studied. Phenol/water extracts from K. pneumoniae 52145DeltawabH waaL and 52145DeltawaaL mutants, but not those from from K. pneumoniae 52145DeltawabG waaL mutant, contained both LPS and capsular polysaccharide, even after hydrophobic chromatography. The two polysaccharides were dissociated by gel-filtration chromatography, eluting with detergent and metal-ion chelators. From these results, it is concluded that the K2 capsular polysaccharide is associated by an ionic interaction to the LPS through the negative charge provided by the carboxyl groups of the GalA residues.
authors.affiliation: Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, Diagonal 645, 08071 Barcelona, Spain.
authors.forename: Sandra
authors.initials: S
authors.lastname: Fresno
authors.affiliation: Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, Diagonal 645, 08071 Barcelona, Spain.
authors.forename: Natalia
authors.initials: N
authors.lastname: Jiménez
authors.affiliation: Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, Diagonal 645, 08071 Barcelona, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Izquierdo
authors.affiliation: Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, Diagonal 645, 08071 Barcelona, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: Merino
authors.affiliation: Dipartimento di Chimica e Biochimica, Università Federico II di Napoli, Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Napoli, Italy.
authors.forename: Maria Michela
authors.initials: MM
authors.lastname: Corsaro
authors.affiliation: Dipartimento di Chimica e Biochimica, Università Federico II di Napoli, Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Napoli, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: De Castro
authors.affiliation: Dipartimento di Chimica e Biochimica, Università Federico II di Napoli, Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Napoli, Italy.
authors.forename: Michelangelo
authors.initials: M
authors.lastname: Parrilli
authors.affiliation: Dipartimento di Chimica e Biochimica, Università Federico II di Napoli, Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Napoli, Italy.
authors.forename: Teresa
authors.initials: T
authors.lastname: Naldi
authors.affiliation: Departamento de Microbiología y Parasitología Sanitarias, Facultad de Farmacia, Universidad de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Regué
authors.affiliation: Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, Diagonal 645, 08071 Barcelona, Spain.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Tomás
mesh_terms: D000818:Animals; D016667:Bacterial Capsules / Q000737:chemistry* / Q000378:metabolism; D002240:Carbohydrate Sequence; D006603:Hexuronic Acids / Q000737:chemistry; D006801:Humans; D007710:Klebsiella Infections / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D018410:Pneumonia, Bacterial / Q000382:microbiology
chemical_list: D006603:Hexuronic Acids; D008070:Lipopolysaccharides; C007819:galacturonic acid