Structural heterogeneity in the O polysaccharide of Pseudomonas syringae pv. coriandricola GSPB 2028 (NCPPB 3780, W-43).

The O polysaccharide (OPS) of the lipopolysaccharide of Pseudomonas syringae pv. coriandricola GSPB 2028 (NCPPB 3780, W-43) was studied by Smith degradation and 1H-NMR and 13C-NMR spectroscopy, including two-dimensional COSY, TOCSY, NOESY, and H-detected 1H,13C heteronuclear multiple-quantum coherence (HMQC) experiments. The OPS was shown to consist of pentasaccharide O repeats of two types both containing four L-rhamnose and one 3-acetamido-3,6-dideoxy-D-galactose (D-Fuc3NAc) residue. Structure 1 of the major O repeat which had been established earlier [Das, S., Ramm, M., Kochanowski, H. & Basu, S. (1994) J. Bacteriol. 176, 6550-6557], was confirmed by our data, and a new structure 2 was elucidated for the minor O repeat and found to differ from the structure 1 only in the position of substitution of one of the rhamnose residues in the main chain. α-D-Fucp3NAc 1 ↓ 2 ←2)-α-L-Rhap-(1←2)-α-L-Rhap-(1←3)-α-L-Rhap-(1←3)-α-L-Rhap-(1← 1 α-D-Fucp3NAc 1 ↓ 2 ←3)-α-L-Rhap-(1←2)-α-L-Rhap-(1←3)-α-L-Rhap-(1←3)-α-L-Rhap-(1← 2 A role of structural and immunochemical features of the LPS for defining the taxonomical position of the bacterium studied is discussed. [ABSTRACT FROM AUTHOR]