ROLE OF N-GLYCOSYLATION IN THE SYNTHESIS, DIMERIZATION AND SECRETION OF HUMAN INTERFERON-GAMMA

摘要: Human interferon-gamma (IFN-gamma) is a secretory glycoprotein, which has two potential N-linked glycosylation sites at positions Asn-25 and Asn-97 of its 143 amino acid long mature polypeptide chain. In order to understand the role glycan residues in synthesis secretion human IFN-gamma, both or either one were mutated Gln. The mutant wild-type (Wt) polypeptides expressed insect cells using baculovirus vector. Elimination N-glycosylation site position (N97Q) resulted secreted protein yields 70-90% as compared with Wt production, whereas only 10-25% (N25Q) 1-10% (N25Q,N97Q) levels production was observed when first mutated, respectively. Although there difference between extracellular produced protein, kinetics similar for all different IFN-gamma molecules. mutants dimers. formation biologically active dimers more efficient that had intact other forms IFN-gamma. extent dimerization correlated well secretion. specific antiviral activity same (1 x 10(7) i.u./mg protein) glycosylated molecules, it slightly lower (0.5 unglycosylated form.