earticle

영어

Glycoprotiens are responsible in many biological events. However oligosaccharides covalently attached to these proteins always exhibit heterogeneity. This has been a hindrance to investigate what oligosaccharide structure is essential for the individual biological event. Therefore we have examined the chemical synthesis of several glycoproteins such as cytokines consist of 70 to 166 amino acid residues. [1-3] However, glycoproteins used in the cell-cell communication or immune response exhibit larger molecular weight comparing with those of cytokines we have synthesized. Unfortunately, the synthesis of such large and homogeneous glycoproteins is still far from our current achievements, because we have not established an efficient method for the synthesis of large glycoproteins yet. Native chemical ligation[4] is a powerful method to couple two polypeptide chains through a native amide bond. This ligation takes place between peptide-C-terminal thioester and cysteine at the N-terminal of another peptide. Using this ligation between glycopeptide-thioester synthesized by chemical method and long peptide prepared from E. coli expression, we have examined the synthesis of large glycoprotein. In this presentation, we would discuss the first synthesis of large and homogeneous glycosylpolypeptide chain (25 kDa) consists of over 200 amino acid residues.