Convergent Approach to the Chemical Synthesis of Asparagine-Linked Glycopeptides

摘要

Reaction conditions for the direct coupling of glycosylamines to aspartic acidcontaining peptides are described. A cotranslational process which is common to the biosynthetic pathways of many cell-surface and secreted eukaryotic proteins involves transfer of (Glc)3(Man)9(-)(GlcNAc)2 to an asparagine amide nucleophile to produce an asparagine-linked glycoprotein. Because it occurs cotranslocationally, glycosylation may play a role in the folding of glycoproteins. In order to model the interactions between the nascent polypeptide chain and the attached oligosaccharide, we have undertaken the chemical synthesis of a series of glycopeptides.