On-bead Screening and Ligand Identification

Library 15 was screened for binding properties to wheat germ agglutinin (WGA) [17]. WGA is a 36 kDa lectin composed of two glycine- and cysteine-rich subunits. 

To quantify their binding to WGA in solution, glycopeptides 16, 18, and 22 were re-synthesized as single compounds. IC50 values for inhibition of the binding of porcine stomach mucin to peroxidase-labeled WGA (Table 2.7.1) were determined by an enzyme-linked lectin assay (ELLA) as described by Zanini and Roy [21]. The IC50 values shown in Table 2.7.1 confirm that the binding behavior of 16, 18, and 

22 in solution is similar to that on the solid phase, so the result of the on-bead screening was not a surface effect, as has been observed by Kahne et al. with an immobilized oligosaccharide library [22]. 

683-720 A. Varki, R. Cummings, J. Esko, H. Freeze, G. Hart, J. Marth, eds., Essentials of Glycobiology, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, 1999 R. S. Haltiwanger, Curr. Opin. Struct. Biol. 2002, 12, 593-598. 

Drickamer, Curr. Opin. Struct. Biol. 1999, 9, 585-590 R. Loris, Biochim. Biophys. Acta 2002, 1572, 198-208. 

---