Oligosaccharides arrays

Figure 6 Dose-response binding curve of lectins to the arrayed oligosaccharides. Con A binding on mannose (A), glucose ( ), and GlcNAc (O) EC on lactose (x) and galactose ( ) LT on fucose ( ). Each data point represents the average value of the mean signaliSD (standard deviation) of 18 replicate spots from 2 slides.

Some membrane proteins are covalently linked to complex arrays of carbohydrate. For example, in gly-cophorin, a glycoprotein of the erythrocyte plasma membrane, 60% of the mass consists of complex oligosaccharide units covalently attached to specific amino acid residues. Ser, Thr, and Asn residues are the most common points of attachment (see Fig. 7-31). At the other end of the scale is rhodopsin of the rod cell plasma membrane, which contains just one hexasac-charide. The sugar moieties of surface glycoproteins influence the folding of the proteins, as well as their sta-... 

Fig. 3.3. Schematic illustration of the proposed architecture of mucus glycoproteins, (a) Subunits constitute a linear array of oligosaccharide clusters interspersed with naked stretches of protein. (b) Trypsin digestion affords glycopeptides corresponding to the oligosaccharide clusters. (c) The whole mucins are formed by an end-to-end association of subunits via disulphide bonds, (d) The hydrodynamic model of mucus glycoproteins conforms to a random coil within a spheroidal solvent domain. (After Allen et al., 1984.)...

Final hydrolysis of di- and oligosaccharides is carried out by surface enzymes of the small intestinal epithelial cells, called the brush border, a term that comes from the appearance of the enterocytes, in which the luminal plasma membrane is enlarged by a regular array of projections called microvilli. The enzymes are not secreted into the lumen, but are embedded in the cell membrane, many of these enzymes can protrude into the intestinal lumen up to 10 gm, as they are attached to the plasma membrane by an anchoring polypeptide that has no role by itself in the hydrolysis. 

Examining protein-carbohydrate interactions in an array format with immobilized carbohydrates has also been reported. In addition to the three reports by our group on protein-carbohydrate interactions with SPRi [31, 32, 47], the Livache group has developed a polypyrrole-based oligosaccharide chip constructed via a copolymerization process of pyrrole and pyrrole-modified oligosaccharide to screen protein-carbohydrate interactions [48]. They covalently immobilized various carbohydrate... 

Mercey E, Sadir R, Maillart E, Roget A, Baleux F, Lortat-Jacob H, Livache T (2008) Polypyrrole oligosaccharide array and surface plasmon resonance imaging for the measurement of glycosaminoglycan binding interactions. Anal Chem 80 3476-3482... 

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