aN. D. Zelinsky Institute of Organic
Chemistry, Russian Academy of Sciences, Moscow, Russia
bCenter of Microbiology and Virology, Polish Academy of Sciences, Lodz, Poland
KEYWORDS: lipopolysaccharide, O-antigen, polysaccharide, L-lysine, structure, NMR spectroscopy, Proteus mirabilis
Biochemistry/Moscow, 1996, v. 61(1), pp. 15-21
Composition and structure of the O-specific polysaccharide chain of the lipopolysaccharide of the bacterium Proteus mirabilis O26 were studied using one- and two-dimensional 1H- and 13C-NMR spectroscopy, including homonuclear correlation spectroscopy (COSY), H-detected 1H,13C heteronuclear multi-quantum coherence, and rotating-frame nuclear Overhauser effect spectroscopy. It was found that the polysaccharide is acidic due to the presence of residues of D-galacturonic acid (D-GalA), part of which are O-acetylated and the other part form an amide with the a-amino group of L-lysine, and is built up of tetrasaccharide repeating units having the following structure:
L-Lys |6 -4)aDGalpA(1-4)aDGalp(1-3)[AcO-4]bDGalpA(1-3)bDGlcpNAc(1-
The P. mirabilis O26 polysaccharide is structurally similar to the O-specific polysaccharide of P. mirabilis O28, which was studied by us earlier and found to contain amides of D-galacturonic acid with L-lysine and L-serine [Eur. J. Biochem. 230, 705-712 (1995)].