title: Characterization of the sugar-binding specificity of the toxic lectins isolated from Abrus pulchellus seeds.
abstract: The sugar-binding specificity of the toxic lectins from Abrus pulchellus seeds was investigated by combination of affinity chromatography of glycopeptides and oligosaccharides of well-defined structures on a lectin-Sepharose column and measurement of the kinetic interactions in real time towards immobilized glycoproteins. The lectins showed strong affinity for a series of bi- and triantennary N-acetyllactosamine type glycans. The related asialo-oligosaccharides interact more strongly with the lectins. The best recognized structures were asialo-glycopeptides from fetuin. Accordingly, the kinetic interaction with immobilized asialofetuin was by far the most pronounced. Human and bovine lactotransferrins and human serotransferrin interacted to a lesser extent. The interaction with asialofetuin was inhibited by galactose in a dose dependent manner. Lactose, N-acetyllactosamine and lacto-N-biose exhibited similar degree of inhibition while N-acetylgalactosamine was a poor inhibitor. These results suggested that the carbohydrate-binding site of the Abrus pulchellus lectins was specific for galactose and possess a remarkable affinity for the sequences lactose [beta-D-Gal-(1-->4)-D-Glc], N-acetyllactosamine [beta-D-Gal-(1-->4)-D-GlcNAc] and lacto-N-biose [beta-D-Gal-(1-->3)-D-GlcNAc].
authors.affiliation: Departamentos de Biologia, Universidade Federal do Ceara, Campus do Pici, Cx. Postal 6033, Fortaleza-Ceara, Brasil, 60.451-970.
authors.forename: M V
authors.initials: MV
authors.lastname: Ramos
authors.forename: A H
authors.initials: AH
authors.lastname: Sampaio
authors.forename: B S
authors.initials: BS
authors.lastname: Cavada
authors.forename: J J
authors.initials: JJ
authors.lastname: Calvete
authors.forename: T B
authors.initials: TB
authors.lastname: Grangeiro
authors.forename: H
authors.initials: H
authors.lastname: Debray
mesh_terms: D029912:Abrus / Q000737:chemistry*; D000818:Animals; D001665:Binding Sites; D002236:Carbohydrate Conformation; D050260:Carbohydrate Metabolism; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry; D002417:Cattle; D002846:Chromatography, Affinity; D006020:Glycopeptides / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D037102:Lectins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D037121:Plant Lectins; D011485:Protein Binding; D012639:Seeds / Q000737:chemistry*; D013379:Substrate Specificity; D020349:Surface Plasmon Resonance
chemical_list: D002241:Carbohydrates; D006020:Glycopeptides; D037102:Lectins; D009844:Oligosaccharides; D037121:Plant Lectins; C016940:abrus agglutinin