Structures of the biological repeating units in the O-chain polysaccharides of Hafnia alvei strains having a typical lipopolysaccharide outer core region

FEMS Immunol Med Microbiol. 2005 Aug 1;45(2):269-78. doi: 10.1016/j.femsim.2005.05.003.

Abstract

Earlier, the structures of the O-chain polysaccharides of the lipopolysaccharides (LPS) of a number of Hafnia alvei strains have been established. However, it remained unknown, which is the first and the last monosaccharide of the O-chain. This is defined by the structure of the so-called biological repeating unit (O-unit), which is pre-assembled and then polymerised in the course of biosynthesis of bacterial polysaccharides by the Wzy-dependent pathway. Now we report on the structures of the O-units in 10 H. alvei strains. The LPS were cleaved by mild acid hydrolysis and oligosaccharide fractions IIIa and IIIb were isolated by gel chromatography subsequently on Sephadex G-50 and BioGel P-2 and studied by methylation analysis and NMR spectroscopy. Fraction IIIb was found to represent the core oligosaccharide containing a terminal upstream alpha-d-Glc-(1-->3)-alpha-d-Glc or alpha-d-Gal-(1-->3)-alpha-d-Glc disaccharide in the outer region that is typical of H. alvei. Fraction IIIa consists of the LPS core with one O-unit linked by a 3-substituted beta-d-GalNAc residue (in strains PCM 1189 and PCM 1546) or a 3-substituted beta-d-GlcNAc residue (in the other strains studied). In most strains examined the beta-configuration of the d-GlcNAc linkage in the first O-unit attached to the core is the same and in some strains is opposite to that found in the interior O-units of the O-chain polysaccharide. Various monosaccharides, including d-Glc, d-Gal, d-GlcA and acyl derivatives of 3-amino-3,6-dideoxy-d-glucose or 4-amino-4,6-dideoxy-d-glucose, occupy the non-reducing end of the O-unit.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbohydrate Conformation
  • Carbohydrate Sequence
  • Chromatography, Gel
  • Gas Chromatography-Mass Spectrometry
  • Hafnia alvei / chemistry*
  • Methylation
  • Molecular Sequence Data
  • Molecular Structure
  • Nuclear Magnetic Resonance, Biomolecular
  • O Antigens / chemistry*
  • Polysaccharides, Bacterial / chemistry*

Substances

  • O Antigens
  • O-specific polysaccharide, Hafnia alvei
  • Polysaccharides, Bacterial