Purification and characterization of an N-acetylglucosamine specific lectin from marine bivalve Macoma birmanica

A calcium independent lectin of molecular mass 47 kDa was isolated from the foot muscle of marine bivalve Macoma birmanica by ammonium sulphate precipitation followed by affinity chromatography on immobilized GlcNAc column and designated as M. birmanica agglutinin (MBA). The lectin agglutinated rabbit erythrocytes strongly compared to human erythrocytes over a wide pH range from 5 to 9 and up to 50 degrees C. MBA is a glycoprotein and consists of 7.63% sugar. Among the tested sugars for analysis of carbohydrate recognition properties, Me-beta GlcNAc was the most potent inhibitor followed by Me-alpha Man. Enzyme linked solid phase assay revealed that MBA interacted well with complex type Winked glycans and moderately to high mannose type Winked glycans. Fluorescence study of MBA indicated that tryptophan was present in a non-hydrophobic region and its binding to GlcNAc was neither quenched nor altered lambda(max) position. The denaturation of MBA induced by urea was a reversible process and urea could not significantly change the Trp environment. MBA interacted with both Gram-positive and Gram-negative bacteria by recognizing their surface exposed GlcNAc containing antigens. (C) 2008 Elsevier Ltd. All rights reserved.