Structure of the O-polysaccharide of Providencia alcalifaciens O2 containing ascarylose and N-(L-alanyl)-D-glucosamine

Carbohydr Res. 2015 Jan 12:401:11-5. doi: 10.1016/j.carres.2014.10.016. Epub 2014 Oct 27.

Abstract

The O-polysaccharide was obtained by degradation of the lipopolysaccharide of Providencia alcalifaciens O2 under mild acidic conditions followed by GPC. The polysaccharide was found to contain two unusual components: 3,6-dideoxy-L-arabino-hexose (ascarylose, Asc) and 2-(L-alanyl)amino-2-deoxy-D-glucose (GlcNAla). Ascarylose was partially split off during lipopolysaccharide degradation and could be eliminated completely by selective acid hydrolysis, which also partially cleaved the β-GAlNAc-(1 → 6) linkage. The following structure of the branched pentasaccharide repeating unit was established by (1)H and (13)C NMR spectroscopy of the O-polysaccharide and O-deacetylated polysaccharide, as well as products of partial acid hydrolysis: α-Ascp-(1 → 4)-α-D-GlcpA-(1 → 4) → 6)-β-D-GlcpNAla-(1 → 4)-β-D-GlpA-(1 → 3)-β-D-GalpNAc-(1 → ~60% OAc--3).

Keywords: Ascarylose; Bacterial polysaccharide structure; Lipopolysaccharide; O-Antigen; Providencia alcalifaciens.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alanine / analogs & derivatives*
  • Alanine / chemistry
  • Carbohydrate Sequence
  • Glucosamine / analogs & derivatives*
  • Glucosamine / chemistry*
  • Hexoses / chemistry*
  • Molecular Sequence Data
  • O Antigens / chemistry*
  • Providencia / chemistry*

Substances

  • Hexoses
  • O Antigens
  • tyvelose
  • Glucosamine
  • Alanine