Abstract
N-glycans in eukaryotic proteins are commonly attached to asparagine residues via β-N-glycosidic linkages, which are susceptible to glycosidases, such as PNGase. Here we report the preparation of α-N-glycosylated peptides based on the solid-phase peptide synthesis strategy using an α-N-GlcNAc-containing asparagine building block, and a transglycosylation reaction of oligosaccharide oxazoline promoted by endoglycosidases CCN180H. The resultant glycopeptide, bearing the complex-type α-N-sialyl undecasaccharide, exhibits resistance against PNGase F, which may be of potential use in studying the catabolism of N-glycans and glycoengineering those peptide-based therapeutics.
Graphical Abstract
Acknowledgements
We also thank Drs. Qin Li, Yuan Wang, and Xiaohui Zhang (Peking University) for spectroscopic assistance.
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Suwei Dong
Prof. Suwei Dong received a B.S. degree from Peking University in 2005, and moved to Boston University and obtained his PhD in 2010 under the guidance of Prof. John Porco. Then he joined Memorial Sloan-Kettering Cancer Center as a postdoctoral scholar under the mentorship of Prof. Samuel Danishefsky, where he worked on the chemical synthesis of therapeutic polypeptides and glycoproteins including erythropoietin. In 2013, Suwei returned back to Peking University and started his independent career at School of Pharmaceutical Sciences. Prof. Dong is currently the Head of the Chemical Biology Department, and his research interests include the development of new methodologies and strategies for the synthesis of glycopeptides and glycoproteins, as well as studying glycan functions through homogeneous glycoproteins obtained via chemical synthesis.