Lipopolysaccharides from Pseudomonas maltophilia: structural studies of the side-chain polysaccharide from strain...

A lipopolysaccharide has been isolated from Pseudomonas maltophilia N.C.T.C. 10257. Monosaccharide components identified were L-rhamnose, 3-O-methyl-L-xylose, L-xylose, D-glucose, D-mannose, D-galacturonic acid, 2-amino-2-deoxy-galactose, 2-amino-2-deoxyglucose, and a 3-deoxy-2-octulosonic acid. Heptose was absent. In this and other respects, the lipopolysaccharide resembles the corresponding products from Xanthomonas species. Mild hydrolysis of the lipopolysaccharide with acid, followed by chromatography of the water-soluble products on Sephadex G-50, gave a polymeric, "side-chain" fraction containing rhamnose, 3-O-methylxylose, and xylose residues in the molar rations approximately 15:4:1. Methylation analysis, periodate oxidation, Smith degradation, and oxidation with chromium trioxide were the principal methods used in the study of this fraction. The following structure is proposed for the characteristic repeating-unit of the polymer.