title: Carbohydrate binding specificity of the basic lectin from winged bean (Psophocarpus tetragonolobus).
abstract: The carbohydrate binding specificity of the basic lectin from winged bean (Psophocarpus tetragonolobus) was investigated by quantitative precipitin analysis using blood group A, B, H, Le and I substances and by precipitation inhibition with various mono- and oligosaccharides. The lectin precipitated best with A1 substances and moderately with B and A2 substances, but not with H or Le substances. Inhibition assays of lectin-blood group A1 precipitation demonstration that A substance-derived oligosaccharides having the common structure: D-GalNAc alpha(1----3)D-Gal-(beta 1----3/4) to a D-Glc, were the best inhibitors and about 8 and 4 times more active than D-GalNAc and D-GalNAc alpha(1----3)D-Gal, respectively. A difucosyl A-specific oligosaccharide (A-penta), a monofucosyl (A-tetra) and a non-fucosyl containing (A5II) oligosaccharide, D-GalNAc alpha(1----3)D-Gal beta(1----3)D-GlcNAc, had almost the same reactivity, suggesting that the fucose linked to the sub-terminal D-Gal or to the third sugar. D-GlcNAc, from the non-reducing end made no contribution to the carbohydrate binding. Although a terminal non-reducing D-GalNAc or D-Gal residue was indispensible for binding, the lectin bound not only to these terminal non-reducing galactopyranosyl residues, but also showed increased binding to oligosaccharides in which it was bonded to a sub-terminal D-Gal joined to a D-GlcNAc residue, as in blood group A or B substances. This defines the site, thus far, as complementary to a disaccharide plus the beta linkage to the third sugar (D-Glc or D-GlcNAc) from the non-reducing end. The role of the beta(1----3) or beta(1----4) linkage of the sub-terminal non-reducing D-Gal to the D-GlcNAc requires further study.
authors.affiliation: Department of Microbiology, College of Physicians and Surgeons, Columbia University, New York, NY 10032.
authors.forename: T
authors.initials: T
authors.lastname: Matsuda
authors.forename: E A
authors.initials: EA
authors.lastname: Kabat
authors.forename: A
authors.initials: A
authors.lastname: Surolia
mesh_terms: D001665:Binding Sites; D050260:Carbohydrate Metabolism; D007887:Fabaceae / Q000378:metabolism*; D037102:Lectins / Q000378:metabolism*; D008958:Models, Molecular; D009005:Monosaccharides / Q000378:metabolism; D009844:Oligosaccharides / Q000378:metabolism; D037121:Plant Lectins; D010946:Plants, Medicinal; D011233:Precipitin Tests
chemical_list: D037102:Lectins; D009005:Monosaccharides; D009844:Oligosaccharides; D037121:Plant Lectins