USE OF PORCINE FIBRINOGEN AS A MODEL GLYCOPROTEIN TO STUDY THE BINDING-SPECIFICITY OF THE 3 VARIANTS OF K88 LECTIN

Known glycoproteins were used to determine the differences occurring i n the binding specificities of the three variants of the K88 lectin in an approach essentially based on lectin blotting. During the screenin g, it was demonstrated that each variant of the K88 lectin biotinylate d via its amino groups (NbioK88) exhibited a characteristic binding to the three chains of porcine fibrinogen. NbioK88ab weakly bound to A a lpha chains, NbioK88ac bound to B beta and gamma chains, and NbioK88ad bound only to the gamma chain. To validate this model, the oligosacch aride moieties of porcine fibrinogen were analyzed with glycosidases a nd by lectin blotting and sugar composition. Both the B beta chain and gamma chain carry biantennary N-glycans of the N acetyllactosamine ty pe that are not recognized by K88 lectins. A alpha chains are substitu ted by sialylated T antigen. O-glycans were also detected on B beta an d gamma chains of porcine fibrinogen and contribute to the recognition of these chains by K88ac and K88ad fimbriae.