title: Purification and characterization of a lectin from the white shrimp Litopenaeus setiferus (Crustacea decapoda) hemolymph.
abstract: A 291-kDa lectin (LsL) was purified from the hemolymph of the white shrimp Litopenaeus setiferus by affinity chromatography on glutaraldehyde-fixed stroma from rabbit erythrocytes. LsL is a heterotetramer of two 80-kDa and two 52-kDa subunits, with no covalently-liked carbohydrate, and mainly composed by aspartic and glutamic acids, glycine and alanine, with relatively lower methionine and cysteine contents. Edman degradation indicated that the NH2-terminal of the 80-kDa subunit is composed DASNAQKQHDVNFLL, whereas the NH2-terminal of the 52-kDa subunit is blocked. The peptide mass fingerprint of LsL was predicted from tryptic peptides from each subunit by MALDI-TOF, and revealed that each subunit showed 23 and 22%, respectively, homology with the hemocyanin precursor from Litopenaeus vannamei. Circular dichroism analysis revealed beta sheet and alpha helix contents of 52.7 and 6.1%, respectively. LsL agglutinate at higher titers guinea pig, murine, and rabbit erythrocytes its activity is divalent cation-dependent. N-acetylated sugars, such as GlcNAc, GalNAc, and NeuAc, were the most effective inhibitors of the LsL hemagglutinating activity. Sialylated O-glycosylated proteins, such as bovine submaxillary gland mucin, human IgA, and fetuin, showed stronger inhibitory activity than sialylated N-glycosylated proteins, such as human orosomucoid, IgG, transferrin, and lactoferrin. Desialylation of erythrocytes or inhibitory glycoproteins abolished their capacity to bind LsL, confirming the relevance of sialic acid in LsL-ligand interactions.
authors.affiliation: Laboratorio de Ecología y Biología Marina Experimental, UMP, Facultad de Ciencias, UNAM. Sisal, Yucatán, C.P. 97130, México.
authors.forename: Juan
authors.initials: J
authors.lastname: Alpuche
authors.forename: Ali
authors.initials: A
authors.lastname: Pereyra
authors.forename: Concepción
authors.initials: C
authors.lastname: Agundis
authors.forename: Carlos
authors.initials: C
authors.lastname: Rosas
authors.forename: Cristina
authors.initials: C
authors.lastname: Pascual
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Slomianny
authors.forename: Lorena
authors.initials: L
authors.lastname: Vázquez
authors.forename: Edgar
authors.initials: E
authors.lastname: Zenteno
mesh_terms: D000818:Animals; D002241:Carbohydrates / Q000737:chemistry; D002413:Cations, Divalent / Q000494:pharmacology; D006384:Hemagglutination / Q000187:drug effects; D006458:Hemolymph / Q000737:chemistry / Q000378:metabolism*; D037102:Lectins / Q000737:chemistry* / Q000302:isolation & purification; D033561:Penaeidae / Q000378:metabolism*
chemical_list: D002241:Carbohydrates; D002413:Cations, Divalent; D037102:Lectins