STRUCTURE OF THE ACIDIC POLYSACCHARIDE CHAIN OF THE LIPOPOLYSACCHARIDE OF SHEWANELLA-ALGA-48055

A lipopolysaccharide (LPS) with an acidic polysaccharide chain was iso lated from the bacterium Shewanella alga strain 48055 and cleaved sele ctively at the glycosidic linkage of N-acetylneuraminic acid to give a tetrasaccharide. Studies of the tetrasaccharide and the O-deacylated LPS by H-1 and C-13 NMR spectroscopy, including 2D COSY, TOCSY, NOESY, rotating-frame NOE spectroscopy (ROESY), and H-detected H-1, C-13 het eronuclear multiple-quantum coherence (HMQC) experiments, revealed the following structure of the polysaccharide repeating unit: >3)-alpha-D -GalpA6GroN-(1-->4)-alpha-NeupSAc-(2--> where GroN is an amidically li nked residue of 2-amino-1,3-propanediol (2-amino-2-deoxyglycerol). A s imilar structure, but with 2-acetamido-2,6-dideoxy-D-glucose instead o f 2-acetamido-2-deoxy-D-glucose, has been reported previously for the polysaccharide chain of a non-O1 Vibrio cholerae H11 LPS [E.V. Vinogra dov, O. Holst, J.E. Thomas-Oates, K.W. Broady, and H. Brade, Eur. J. B iochem., 210 (1992) 491-498]. (C) 1998 Elsevier Science Ltd. All right s reserved.