A D-galactose-binding lectin purified from coronate moon turban, Turbo (Lunella) coreensis, with a unique amino acid sequence and the ability to recognize lacto-series glycosphingolipids

Abstract

A divalent, cation-independent d-galactose-binding lectin was purified from coronate moon turban Turbo (Lunella) coreensis. This lectin recognizes d-galactose and is a 38-kDa dimeric protein consisting disulphide-bonded 22-kDa polypeptides under non-reducing and reducing conditions of sodium dodecyl sulphate-polyacrylamide gel electrophoresis, respectively. Haemagglutination activity was inhibited by D-galactose, N-acetyl D-galactosamine, melibiose, lactose, porcine stomach mucin, asialofetuin and bovine submaxillary mucin. The lectin has tolerance for pH 5-11 and temperature until 50°C for 1h. The lectin strongly aggregated Gram-negative bacteria, such as Vibrio parahaemolyticus and Salmonella O7, but weakly Gram-positive strain as Staphylococcus aureus and Bacillus subtilis. The glycan-binding profile of this lectin was evaluated using frontal affinity chromatography technology and the lectin appeared to recognize oligosaccharides such as lacto-series glycosphingolipids contained in blood type A and H substances in addition to complex-type N-linked glycoproteins. Partial primary structures of 139 amino acid residues of this lectin were determined from N-terminus polypeptides and 8 peptides derived by cleavage with lysyl-endopeptidase. The primary structure was slightly similar to other known sequences of lectin; however, a repeating motif has been included.