Lectins from Tropical Sponges

• Published in: The Journal of biological chemistry Vol. 275; no. 38; pp. 29283 - 29289
• Main Authors: Miarons, Pedro Bonay, Fresno, Manuel
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 22.09.2000; American Society for Biochemistry and Molecular Biology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M001366200

Only a few animal phyla have been screened for the presence and distribution of lectins. Probably the most intensively studied group is the mollusk. In this investigation, 22 species from 12 families of tropical sponges collected in Los Roques National Park (Venezuela) were screened for the presence of lectins. Nine saline extracts exhibited strong hemagglutinating activity against pronase-treated hamster red blood cells; five of these reacted against rabbit red blood cells, four with trypsin-treated bovine red blood cells, and five with human red blood cells regardless of the blood group type. Extracts from the three species studied from genusAplysina (archeri, lawnosa, andcauliformis) were highly reactive and panagglutinating against the panel of red blood cells tested. The lectins from A. archeri and A. lawnosa were purified to homogeneity by ammonium sulfate fractionation, affinity chromatography onp-aminobenzyl-β-1-thiogalactopyranoside-agarose, and gel filtration chromatography. Both lectins exhibited a native molecular mass of 63 kDa and by SDS-polyacrylamide gel electrophoresis under reducing conditions have an apparent molecular mass of 16 kDa, thus suggesting they occur as homotetramers. The purified lectins contain 3–4 mol of divalent cation per molecule, which are essential for their biological activity. Hapten inhibition of hemagglutination was carried out to define the sugar binding specificity of the purifiedA. archeri lectin. The results indicate a preference of the lectin for nonreducing β-linked d-Gal residues being the best inhibitors of red blood cells binding methyl-β-d-Gal and thiodigalactoside (Galβ1–4-thiogalactopyranoside). The behavior of several glycans on immobilized lectin affinity chromatography confirmed and extended the specificity data obtained by hapten inhibition.