Structural determination of the K14 capsular polysaccharide from an ST25 Acinetobacter baumannii isolate, D46

Carbohydr Res. 2015 Nov 19:417:52-6. doi: 10.1016/j.carres.2015.09.002. Epub 2015 Sep 9.

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.

Keywords: Acinetobacter baumannii; Capsular polysaccharide; Capsule; K locus; KL14 gene cluster.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acinetobacter Infections / microbiology
  • Acinetobacter baumannii / chemistry*
  • Acinetobacter baumannii / genetics
  • Acinetobacter baumannii / isolation & purification
  • Acinetobacter baumannii / metabolism
  • Antigens, Bacterial / chemistry*
  • Bacterial Capsules / chemistry*
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Carbohydrate Sequence
  • Drug Resistance, Multiple, Bacterial
  • Gene Expression
  • Genetic Loci
  • Glycosyltransferases / genetics*
  • Glycosyltransferases / metabolism
  • Humans
  • Magnetic Resonance Spectroscopy
  • Molecular Sequence Data
  • Multigene Family*

Substances

  • Antigens, Bacterial
  • Bacterial Proteins
  • capsular polysaccharide K14
  • Glycosyltransferases