Somatic antigens of pseudomonads: structure of the O-specific polysaccharide of Pseudomonas fluorescens IMV 2366 (biovar C)

The O-specific polysaccharide of P. fluorescens IMV 2366 was studied by sugar and methylation analyses along with 1H and 13C NMR spectroscopy, including 2D gsCOSY, TOCSY, gsNOESY, H-detected 1H,13C gsHSQC, HMQC–TOCSY, and gsHMBC experiments. The polysaccharide contains l-rhamnose, 2-acetamido-2,6-dideoxy-d-galactose (d-FucNAc) and 3-acylamido-3,6-dideoxy-d-glucose (d-Qui3NAcyl, where Acyl is 3-hydroxy-2,3-dimethyl-5-oxoprolyl). The structure 1 of the polysaccharide was found to be similar to the structure 2 of a 6-deoxy-l-talose (l-6dTal)-containing O-specific polysaccharide of a non-classified P. fluorescens strain, 361, studied earlier [Khomenko, V. A.; Naberezhnykh, G. A.; Isakov, V. V.; Solovʹeva, T. F.; Ovodov, Y. S.; Knirel, Y. A.; Vinogradov, E. V. Bioorg. Khim. 1986, 12, 1641–1648; Naberezhnykh, G. A.; Khomenko, V. A.; Isakov, V. V., Elʹkin, Y. N.; Solovʹeva, T. F.; Ovodov, Y. S. Bioorg. Khim. 1987, 13, 1428–1429].→2)-β-d-Quip3NAcyl-(1→3)-α-l-Rhap-(1→3)-α-d-FucpNAc-(1→1→4)-β-d-Quip3NAcyl-(1→3)-α-l-6dTalp4Ac-(1→3)-α-d-FucpNAc-(1→2