Structure of the O-polysaccharide of Edwardsiella tarda PCM 1150 containing an amide of D-glucuronic acid with L-alanine

Mild acid degradation of the lipopolysaccharide of Edwardsiella tarda PCM 1150 afforded an O-polysaccharide, which was isolated by GPC on Sephadex G-50 and studied by sugar and methylation analyses along with 1D and 2D H-1 and C-13 NMR spectroscopies, including experiments performed in a 9: 1 H2O/D2O mixture to detect NH protons and their correlations with CH protons. The O-polysaccharide was found to contain an amide of D-glucuronic acid with L-alanine (D-GlcA6Ala) and the following structure of the branched hexasaccharide repeating unit was established: [GRAPHICS] (C) 2013 Elsevier Ltd. All rights reserved.