Carbohydrate binding specificities of several poly-N-acetyllactosamine-binding lectins

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Abstract
The structural requirements for the interaction of the Asn-linked poly-N-acetyllactosamine-type oligosaccharide moieties of glycoproteins with variousN-acetylglucosamine-binding lectins were investigated by means of affinity chromatography on immobilized lectin-Sepharose columns. High molecular weight glycopeptides containing poly-N-acetyllactosamine-type oligosaccharides obtained by Pronase digestion of human erythrocyte ghosts were treated with 0.1 M trifluoroacetic acid at 100°C for 40 min and then several oligosaccharide fragments were purified with an amino-bonded silica column. Among these oligosaccharide fragments, trisaccharide Galβ1-4GlcNAcβ1-6Galol bound to the wheat germ agglutinin (WGA)- and pokeweed mitogen (PWM)-Sepharose columns, and also showed affinity to theDatura stramonium agglutinin (DSA)-,Lycopersicon esculentum (tomato) agglutinin-andSolanum tuberosum (potato) agglutinin-Sepharose columns. Pentasaccharide Galβ1-4GlcNAcβ1-3(Galβ1-4GlcNAcβ1-6)Galol showed weaker affinity to the WGA- and PWM-Sepharose columns, compared to the trisaccharide. Trisaccharide GlcNAcβ1-3(GlcNAcβ1-6)Galol showed weak affinity to the WGA-Sepharose column and did not show any affinity to the other lectin-Sepharose columns. Hexasaccharide Galβ1-4GlcNAcβ1-3Galβ1-4GlcNAcβ1-3Galβ1-4GlcNAcol bound only to the DSA-Sepharose column, indicating that only DSA does not require a GlcNAcβ(1-6)-linkage for interaction.