Sialylated oligosaccharides, selectins binding

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-... 

Carbohydrate-mediated cell adhesion is an important event which can be initiated by tissue injury or infection and is involved in metastasis. One such adhesion process is the interaction between the glycoprotein E-selectin and oligosaccharides on the surface of neutrophils (white blood cells). The ligand that E-selectin recognizes is the tetrasaccharide sialyl Lewis X (SLe ). Since SLe competes with white blood cells for binding to E-selectin, thus inhibiting the adhesion process, it may useful as an anti-inflammatoiy and anticancer agent. 

Ng, K. K.-S., Weis, W I, Stmcture of a selectin-like mutant of mannose-binding protein complexed with sialylated and sulfated Lewis oligosaccharides. Biochemistry, 36, 979-988, 1997. 

The involvement of sialic acid in the interaction of leukocyte adhesion receptors of the selectins with their ligands has been a subject of numerous reviews. It is obvious from these studies that sialic acid is involved in this interaction because of the charge of its carboxylic group that can be substituted with sulfate [220]. More recently, selectin/mannose-binding protein chimeras have been constructed to understand the mechanism involved in the binding of sialylated Lexis oligosaccharide by this receptor [221]. 

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