A Universal Approach to C-Terminal Thioesters for Protein Synthesis

Principal Investigator: Champak Chatterjee

Native chemical ligation (NCL) is a powerful method for producing protein-based therapeutics and antibiotics. NCL enables total synthesis of full-length proteins by chemoselectively combining two different polypeptide chains, one with a C-terminal peptide thioester and the other with a N-terminal cysteine thiol. Polypeptides bearing the N-terminal Cys may be prepared for NCL by using a protecting group called Fmoc. However, Fmoc chemistry is often incompatible with C-terminal thioesters. Therefore, there is a need for a functional group tolerant, synthetically facile strategy for producing these thioesters to enable this low-cost, flexible method for producing proteins.

Professor Champak Chatterjee and his students have developed a facile and universal approach to synthesis of C-terminal peptide thioesters. Using N-mercaptoethoxyglycinamide (MEGA), they have demonstrated that peptides synthesized with the C-terminal MEGA moiety are readily converted to their thioester form under optimized conditions, and may be directly applied toward NCL. This strategy is compatible with most C-terminal amino acids, including sterically hindered residues. The resulting approach is applicable to inter- and intramolecular one-pot NCL synthesis of proteins, particularly cyclic proteins often used as antibiotics. It is envisioned that this approach will enable production a class of solid phase protein synthesis (SPPS) resins featuring C-terminal amino acids suitable for inexpensive and efficient one-pot protein synthesis.


• Native chemical ligation/protein synthesis 

• SPPS resins


• Facile, universally applicable approach to C-terminal thioesters 

• Enables inexpensive one-pot NCL reactions, particularly for cyclic peptides

Available for Licensing and Sponsored Research Support

For more info, contact: Forest Bohrer