title: The lectin from the crustacean Liocarcinus depurator recognizes O-acetylsialic acids.
abstract: A lectin that recognized sialic acids and aggultinated mouse erythrocytes was purified from hemolymph of the crab Liocarcinus depurator. It consisted of 38-kDa subunits and had a pI about 6.0. The specificity of the lectin was assayed by hemagglutination inhibition. N-acetylneuraminic acid (Neu5Ac) was a good inhibitor and its N-acetyl group at C-5 was critical for lectin-ligand interaction. Substitution of the C-9 hydroxyl on Neu5Ac with an O-acetyl group (9-O-Ac-Neu5Ac) increased the inhibitory potency of this molecule. Furthermore, O-acetyl substitution of all the hydroxyl groups yielded even better inhibitors (2,4,7,8,9-O-Ac-Neu5Ac and its 1-O-methyl ester). Removal of the hydroxyl or O-acetyl group connected to C-2 reduced the potency of these inhibitors. The lectin agglutinated and stimulated human but not mouse lymphocytes. It was also inhibited by Escherichia coli (O111:B4) lipopolysaccharide and agglutinated specific gram-negative bacteria. In vitro labeling with [35S]methionine indicated that the lectin was synthesized in hepatopangreas of L. depurator. Immunofluorescence showed that among hemocytes it localized mainly in the large-granule population.
authors.affiliation: Institute of Molecular Biology-Biotechnology, University of Crete, Greece.
authors.forename: G A
authors.initials: GA
authors.lastname: Fragkiadakis
authors.forename: E K
authors.initials: EK
authors.lastname: Stratakis
mesh_terms: D000372:Agglutination Tests; D000818:Animals; D002241:Carbohydrates / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D003445:Crustacea / Q000737:chemistry*; D006023:Glycoproteins / Q000494:pharmacology; D006458:Hemolymph / Q000737:chemistry; D006801:Humans; D037102:Lectins / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D008214:Lymphocytes / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D051381:Rats; D012794:Sialic Acids / Q000378:metabolism* / Q000494:pharmacology; D013379:Substrate Specificity
chemical_list: D002241:Carbohydrates; D006023:Glycoproteins; D037102:Lectins; D012794:Sialic Acids; C025676:9-O-acetyl-N-acetylneuraminic acid