title: Purification and characterization of a T-antigen specific lectin from the coelomic fluid of a marine invertebrate, sea cucumber (Holothuria scabra).
abstract: A novel lectin was purified from the coelomic fluid of the sea cucumber Holothuria scabra (HSL), subjected to bacterial challenge. HSL is a monomeric glycoprotein of molecular mass 182 kDa. The lectin is highly thermostable as it retains full activity for 1 h at 80 degrees C. Further, the hemagglutination activity of HSL is unaffected by pH in the range 2-11. Unlike other lectins purified from marine invertebrates, the hemagglutination activity of HSL does not require any divalent metal ions. The affinity profile of HSL was studied by a combination of hemagglutination inhibition and fluorescence spectroscopy. HSL binds to desialylated glycoproteins, MealphaGal, T-antigen and T (alpha-ser)-antigen with a distinction between beta1-4 and beta1-3 linkages. Mealpha-T-antigen was a potent ligand having highest affinity (Ka 8.32 x 10(7)M(-1)). Monosaccharide binding is enthalphically driven while disaccharide binding involves both entropic and enthalpic contributions.
authors.affiliation: Gene Laboratory, National Institute of Oceanography, Dona Paula, Goa 403 004, India.
authors.forename: Nagaraj M
authors.initials: NM
authors.lastname: Gowda
authors.forename: Usha
authors.initials: U
authors.lastname: Goswami
authors.forename: M Islam
authors.initials: MI
authors.lastname: Khan
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000941:Antigens / Q000276:immunology / Q000378:metabolism*; D001826:Body Fluids / Q000737:chemistry*; D002241:Carbohydrates / Q000032:analysis; D002413:Cations, Divalent / Q000494:pharmacology; D002942:Circular Dichroism; D005453:Fluorescence; D006385:Hemagglutination Inhibition Tests; D047332:Holothuria / Q000737:chemistry* / Q000276:immunology; D006863:Hydrogen-Ion Concentration; D037102:Lectins / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism; D013058:Mass Spectrometry; D008970:Molecular Weight; D012680:Sensitivity and Specificity; D013696:Temperature
chemical_list: D000596:Amino Acids; D000941:Antigens; D002241:Carbohydrates; D002413:Cations, Divalent; D037102:Lectins