STRUCTURE OF A NEW LYSINE-CONTAINING O-SPECIFIC POLYSACCHARIDE OF THEBACTERIUM PROTEUS-MIRABILIS O26

Composition and structure of the O-specific polysaccharide chain of th e lipopolysaccharide of the bacterium Proteus mirabilis O26 were studi ed using one- and two-dimensional H-1- and C-13-NMR spectroscopy, incl uding homonuclear correlation spectroscopy (COSY)(4), H-detected H-1,C -13 heteronuclear multi-quantum coherence, and rotating-frame nuclear Overhauser effect spectroscopy. It was found that the polysaccharide i s acidic due to the presence of residues of D-galacturonic acid (D-Gal A), part of which is O-acetylated and the other part forms an amide wi th the or-amino group of L-lysine, and is built up of tetrasaccharide repeating units having the following structure: [GRAPHICS] The P. mira bilis O26 polysaccharide is structurally similar to the O-specific pol ysaccharide of P. mirabilis O28, which was studied by us earlier and f ound to contain amides of D-galacturonic acid with L-lysine and L-seri ne.