O-polysaccharides

Following with bacterial infections and anti-adhesion strategies,86 88 NMR based structural studies have been conducted on O-polysaccharide chains in these past few years,38 40,42,43 in order to elucidate the molecular basis and the role of the lipopolysaccharides in these pathologies. 

The ID ge-NOESY-TOCSY experiment is illustrated using a EPS O-polysaccharide (7) isolated from Proteus mirabilis serotype 0 57 [79]. The... 

L. A. Mutant, P. Kovac, and C. P. J. Gilandemans, Synthesis of specifically monofluorinated ligands related to the O-polysaccharide of Shigella dyserUeriae type 1, Carbohydr. Res. 259 21 (1994). 

The same linkage sequence has been recently described for the O-polysaccharide of the lipopolysaccharide of Lanyl strain 0 7a,b of Pseudomonas aeruginosa this strain is possibly identical to Fisher type 2 (20). 

Phage P22 lyses bacteria belonging to serogroups A, B and D. Rough mutants, lacking the O-polysaccharide chain, and semi-rough mutants, with one repeating unit only, are resistant (33, 34). 

Fig. 1. Schematic representation of the three distinct regions of LPS. The repating unit structure of the O-polysaccharide may be recognized by antibodies with specificities for determinants associated with the terminal non-reducing residues (antibody type 1 b) or internal sequences often spanning more than one repeating sequence (cf. Refs. [72, 73])...

Much of the current knowledge of the biosynthesis of bacterial O-polysaccharide assembly was derived from early studies of the polysaccharides of Salmonella sero-group E [13]. This group consists of a series of four closely related structures belonging to the serogroups Ex - E4 (Table 2). The basic main chain sequence of three monosaccharides, Man-Rha-Gal, seen in the D2 serogroup is the structural element of all four polysaccharides however, in serogroups El5 E2 and E3, E4 the variation oc-... 

Shigella flexneri LPSs comprise a large family of interrelated O-polysaccharide structures, the simplest of which belongs to the Y variant polysaccharide (Table 3). This has a tetrasaccharide repeating unit containing three L-rhamnose residues and... 

The O-polysaccharides of Shigella dysenteriae are structurally very distinct from those of the S. flexneri [20] and have been the subject of synthetic studies in which a branched pentasaccharide of the serotype 2 antigen was prepared [96],... 

The branching 3,6-dideoxyhexoses are exclusively a-linked to the main chain mannose residues of the O-polysaccharide and for paratose and abequose this requires the formation of a 1,2-cis-glycopyranoside bond [8]. Thus, glycosyl halides with the ribo and xylo configuration are required with a nonparticipating group at... 

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