A sheep hydatid cyst glycoprotein as receptors for three toxic lectins, as well as ABRUS PRECATORIUS and RICINUS COMMUNIS agglutinins

Journal/Book: Biochim. Biophys. Acta 1243 (1), 124-128. 1995;

Abstract: The binding properties of a glycoprotein with blood group P1 specificityisolated from sheep hydatid cyst fluid with Gal and GalNAc specificlectins was investigated by quantitative precipitin and precipitininhibition assays. The glycoprotein completely precipitated Ricinuscommunis agglutinin (RCA1), Abrus precatorius agglutinin (APA) andMistletoe toxic lectin-I (ML-I). Only 1.0 microgram of P1 glycoproteinwas required to precipitate 50% of 5.1 micrograms ML-I nitrogen. It alsoreacted well with abrin-a and ricin, precipitating over 73% of thelectin nitrogen added, but poorly or weakly with Dolichos biflorus(DBL), Vicia villosa (VVL, a mixture of A4, A2B2 and B4), VVL-B4,Arachis hypogaea (PNA), Maclura pomifera (MPL), Bauchinia purpurea alba(BPL) and Wistaria floribunda (WFL) lectins. When an inhibition assay inthe range of 5.1 micrograms N to 5.9 micrograms N of lectins (ML-I,abrin-a; ricin, RCA1, and APA, and 10 micrograms P1 active glycoproteininteraction was performed; from 76 to 100% of the precipitations wereinhibited by 0.44 and 0.52 mumol of Gal alpha 1--> 4Gal and Gal beta1--> 4GlcNAc, respectively, but not or insignificantly with 1.72 mumol ofGlcNAc. The Gal alpha 1--> 4Gal disaccharide found in this P1 activeglycoprotein is a frequently occurring sequence of manyglycosphingolipids located at the surface of mammalian cell membranes,especially human erythrocytes and intestinal cells for ligand bindingand microbial toxin attachment. The present finding suggests that theGal alpha 1--> 4Gal beta 1--> 4GlcNAc sequence in this P1 activeglycoprotein is one of the best glycoprotein receptors for three toxiclectins (ricin, abrin-a, and ML-I) as well as for APA, and RCA1, and theresult of inhibition assay implies that these lectins are recognizingpart or all of the Gal alpha 1--> 4Gal beta 1--> 4GlcNAc sequence in theP1 active glycoprotein. Author.

Keyword(s): ANIMAL

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