Structural studies of the O-specific polysaccharide of Hafnia alvei strainPCM 1207 lipopolysaccharide

The structure of the O-specific side-chain of the Hafnia alvei strain PCM 1 207 lipopolysaccharide (LPS) has been investigated. Methylation analysis, p artial acid hydrolysis, matrix-assisted laser-desorption ionization time-of -flight (MALDI-TOF) MS, fast atom bombardment (FAB)-MS/MS and H-1- and C-13 -NMR spectroscopy were the principal methods used. Glycerol phosphate was i dentified as a constituent in the polysaccharide and the following structur e of a pentasaccharide repeating unit was established: -->3)-beta-D-GalpNAc -(1-->4)-beta-D-GalpNAc(1-->3)-alpha-D-Galp-(1-->4)-beta-D-Galp-(1--> [GRAPHICS] The polysaccharide is partially (approximate to 10%) substituted with O-ace tyl groups. The lipopolysaccharide was also subjected to high resolution ma gic angle spinning (HR-MAS) NMR analysis, which showed both the signals of the O-specific polysaccharide as well as several signals from unsubstituted con oligosaccharides. This confirmed the presence of the described structu re in the native LPS.