STRUCTURE OF THE N-LINKED OLIGOSACCHARIDES FROM TRIDACNIN, A LECTIN FOUND IN THE HEMOLYMPH OF THE GIANT CLAM HIPPOPUS-HIPPOPUS

Tridacnin, a glycoprotein lectin, was isolated from the symbiotic mari ne clam Hippopus hippopus and the structure of its major N-glycan chai ns determined. Tridacnin contains only N-linked glycans which were qua ntitatively cleaved by peptide-N-4-(N-acetyl-beta-glucosaminyl)asparag ine amidase F. Following purification by anion-exchange HPLC, the stru ctures of the oligosaccharides were established using a combination of electrospray ionisation mass spectrometry, H-1-NMR spectroscopy and l inkage analysis. The N-glycans are primarily of the oligomannose type but, in addition, some contain a novel 6-O-Me group on the terminal ma nnose residue of the chain. The N-glycan chains had the following stru ctures. [GRAPHICS] 6-O-Me-Man(7)GlcNAc(2);Man(6)GlcNAc(2)