title: Structural determination of the K14 capsular polysaccharide from an ST25 Acinetobacter baumannii isolate, D46.
abstract: The structure of the capsular polysaccharide (CPS) recovered from D46, an extensively antibiotic resistant ST25 Acinetobacter baumannii clinical isolate, was elucidated. The structure was resolved on the basis of NMR spectroscopy and chemical analyses, and was found to contain a branched neutral pentasaccharide with a backbone composed of GalpNAc and Galp residues, all d configured, and a d-Glcp side group. The KL14 gene cluster found in the D46 genome includes genes for four glycosyltransferases but no modules for synthesis of complex sugars, and this is consistent with the structure of K14. The K14 structure and KL14 sequence clarify the relationship between the structure and K locus sequence for A. nosocomialis isolate LUH5541. The identity of the first sugar of the K14 repeat unit (K unit), and the functions of the four encoded glycosyltransferases and Wzy polymerase were predicted.
authors.affiliation: School of Molecular Bioscience, The University of Sydney, Sydney, NSW, 2006, Australia; School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, 4001, Australia.
authors.forename: Johanna J
authors.initials: JJ
authors.lastname: Kenyon
authors.affiliation: School of Molecular Bioscience, The University of Sydney, Sydney, NSW, 2006, Australia.
authors.forename: Ruth M
authors.initials: RM
authors.lastname: Hall
authors.affiliation: Department of Agriculture, via Università 100, Portici, NA, Italy. Electronic address: decastro@unina.it.
authors.forename: Cristina
authors.initials: C
authors.lastname: De Castro
mesh_terms: D000151:Acinetobacter Infections / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D000942:Antigens, Bacterial / Q000737:chemistry*; D016667:Bacterial Capsules / Q000737:chemistry*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002240:Carbohydrate Sequence; D024901:Drug Resistance, Multiple, Bacterial; D015870:Gene Expression; D056426:Genetic Loci; D016695:Glycosyltransferases / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D005810:Multigene Family
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C039514:capsular polysaccharide K14; D016695:Glycosyltransferases
keywords: Acinetobacter baumannii; Capsular polysaccharide; Capsule; K locus; KL14 gene cluster