Structural requirements for the binding of oligosaccharides and glycopeptides to immobilized wheat germ agglutinin

Abstract

The structural requirements for the interaction of asparagine-linked oligosaccharide moieties of glycoproteins with wheat germ agglutinin (WGA) were investigated by using affinity chromatography on a WGA-Sepharose column. Hybrid-type glycopeptides obtained from ovalbumin had a high affinity for WGA-Sepharose; high mannose-type and complex-type glycopeptides had low affinity. The elution profiles of various glycopeptides modified by glycosidase treatment, Smith periodate degradation, acetolysis and hydrazinolysis showed that the structure was essential for binding of glycopeptides to a WGA-Sepharose column. Both the N,N''-diacetylchitobiose moiety and the .beta.-N-acetylglucosaminyl residue linked to C-4 of the .beta.-linked mannose residue contributed to the interaction of the glycopeptide with WGA-Sepharose. The substitution at C-6 of the innermost .beta.-N-acetylglucosaminyl residue by an .alpha.-fucosyl residue or at C-6 of the .beta.-linked mannose residue by another mannose residue in the above structure reduced the affinity of glycopeptides for the column.