Oligosaccharides sialylations

The precise chemical nature of some of the ligands involved in selectin-ligand interactions has been determined. All three selectins bind sialylated and fucosy-lated oligosaccharides, and in particular all three bind sialyl-Lewis (Figure 47-12), a structure present on both glycoproteins and glycolipids. Whether this compound is the actual ligand involved in vivo is not estab-... 

Shen, Z., Warren, C.D., and Newburg, D.S., High-performance capillary electrophoresis of sialylated oligosaccharides of human milk, Anal. Biochem., 279, 37, 2000. 

Fig. 19. Cyclodextrins decorated with sugars, including sialic acid and sialyl oligosaccharides. 

Several other examples of successful application of sialyl xanthates for oligosaccharide synthesis have been reported [411,413-427]. 

The data for these oligosaccharides have been incorporated into the molecular models shown in Figs. 3 and 4. The conformation and molecular recognition of sialylated oligosaccharides are an important area for future investi-... 

Fig. 3—Possible solution conformers of oligosaccharide sequences related to the Le and Leb antigens (Lea,Lex, sialyl Le", sialyl Lex, ALeb, ALey). As described in the text, oligosaccharides in solution sample 3D space in local energy-minima wells, so that the conformations shown are approximate only. The models stand only to show the stereochemical hindrance to movement in these branched oligosaccharides. The molecules are shown without the anomeric hydroxyl group. 

Figure 14.2 Representative oligosaccharide structures found on mammalian glycoproteins and glycolipids. The complex oligosaccharides may be bi-, tri-, or tetra-antennary the branches may be more or less elongated with 1—>4 linked lactosamine units, and they may or may not be sialylated. The SLex, Lea, and Leb structures represent the different blood group determinants often present on lipids, and the elongated core 2 structure is a mucin-type glycosylation. Proteoglycans have a common core to which a variety of linear acidic polysaccharides are attached.

Barthelson, R., Mobasseri, A., Zopf, D., and Simon, P. (1998). Adherence of Streptococcus pneumoniae to respiratory epithelial cells is inhibited by sialylated oligosaccharides. Infect. Immun. 66,1439-1444. 

Martin-Sosa, S., Martin, M.-J., and Hueso, P. (2002). The sialylated fraction of milk oligosaccharides is partially responsible for binding to enterotoxigenic and uropathogenic Escherichia coli human strains. /. Nutr. 132,3067-3072. 

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