New Directions in Glycoprotein Engineering

Semisynthetic protein engineering techniques can be employed to overcome classic bottlenecks in the total synthesis or recombinant production of proteins bearing natural or unnatural post-translational modifications. Glycoproteins are particularly suited to semisynthesis as homogeneous samples for biological analyses are not readily available using traditional recombinant techniques. Here we report the use of expressed protein ligation for the construction of semi-synthetic glycoproteins, which are assembled when recombinantly derived peptide α-thioesters are covalently joined with synthetic glycopeptides with clustered O-linked glycans by native chemical ligation. We demonstrate how this approach may be employed for the construction of glycoproteins bearing mucin-like domains.