The structure of the O-polysaccharide from Pseudomonas stutzeri OX1 containing two different 4-acylamido-4,6-dideoxy-residues, tomosamine and perosamine.

The structure of the O-polysaccharide from the lipopolysaccharide of Pseudomonas stutzeri OX1 was determined by chemical procedures and by 1D and 2D NMR spectroscopy. The analysis revealed the presence of a heterogeneous polymer made by 4-acetamido-4,6-dideoxy-D-mannopyranose (D-Rhap4NAc) and 4-formamido-4,6-dideoxy-D-galactopyranose (d-Fucp4NFo). The combination of chemical and NMR analyses indicates that the heterogeneity of the polymer depends on its non-stoichiometric glycosylation by Fuc4NFo, as shown below: [formula: see text]. The structure of the heterogeneous polymer was confirmed by Smith degradation that significantly simplified the structure of the O-polysaccharide, allowing for the isolation and identification of a linear homopolymer of Rhap4NAc.