Structure of a new 2-deoxy-2[-(R)-3-hydroxybutyramido]-D-glucose-containing O-specific polysaccharide from the lipopolysaccharide of Citrobacter gillenii PCM 1542

摘要

The O-specific polysaccharide of Citrobacter gillenii PCM 1542 from serotype O-12a, 12b is composed of one residue each of D-glucose, D-GlcNAc, 2-deoxy-2-[(R)-3-Hydroxybutyramido]-D-glucose (D-GlcNAcyl) and two GalNAc residues. On the basis of sugar and methylation analysis of the intact and Smith degraded polysaccharides, along with 1D and 2D ~1H and ~13C NMR spectroscopy, the following structure of the branched pentasaccharide repeating unit of the O-specific polysaccharide was established: alpha-D-GlcpNAc 1->4 ->6)-beta-D-GlcpNAcy-(1->3)-alpha-D-GlapNAc-(1->3)-beta-D-GlapNAc-(1->6<-1-alpha-D-GlcpThis structure differs significantly from that of the O-specific polysaccharide of C. gillenii PCM 1544 from the same serotype O-12a, 12b, which has been established earlier (Kubler-Kielb, J. et al. Carbohydr. Res. 2001, 331, 331-336). Serologcial studies confirmed that the two O-antigens are not related and suggested that strains PCM 1542 and 1544 should be classified into different O-serogroups.