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

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 Gal1-4GlcNAc1-6Galol 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 Gal1-4GlcNAc1-3(Gal1-4GlcNAc1-6)Galol showed weaker affinity to the WGA- and PWM-Sepharose columns, compared to the trisaccharide. Trisaccharide GlcNAc1-3(GlcNAc1-6)Galol showed weak affinity to the WGA-Sepharose column and did not show any affinity to the other lectin-Sepharose columns. Hexasaccharide Gal1-4GlcNAc1-3Gal1-4GlcNAc1-3Gal1-4GlcNAcol bound only to the DSA-Sepharose column, indicating that only DSA does not require a GlcNAc(1-6)-linkage for interaction.Abbreviations HPLC high performance liquid chromatography - WGA wheat germ agglutinin - PWM pokeweed mitogen - DSA Datura stramonium agglutinin - LEA Lycopersicon esculentum (tomato) agglutinin - STA Solanum tuberosum (potato) agglutinin - EVA Erythrina variegata agglutinin - PBS 10 mM sodium phosphate buffer, pH 7.2, containing 0.15 M NaCl - Galol galactitol - GlcNAcol N-acetylglucosaminitol