New directions in glycoprotein engineering

Semisynthetic protein engineering techniques can be employed to overcome cl assic bottlenecks in the total synthesis or recombinant production of prote ins bearing natural or unnatural post-translational modifications. Glycopro teins are particularly suited to semisynthesis as homogeneous samples for b iological analyses are not readily available using traditional recombinant techniques. Here we report the use of expressed protein ligation for the co nstruction of semi synthetic glycoproteins, which are assembled when recomb inantly derived peptide alpha -thioesters are covalently joined with synthe tic glycopeptides with clustered O-linked glycans by native chemical ligati on. We demonstrate how this approach may be employed for the construction o f glycoproteins bearing mucin-like domains. (C) 2000 Elsevier Science Ltd. All rights reserved.