Characterization of the sugar-binding specificity of the toxic lectins isolated from Abrus pulchellus seeds

Autor: M V, Ramos, A H, Sampaio, B S, Cavada, J J, Calvete, T B, Grangeiro, H, Debray
Rok vydání: 2002
Předmět:
Zdroj: Glycoconjugate journal. 18(5)
ISSN: 0282-0080
Popis: 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].
Databáze: OpenAIRE