Ser/Thr Ligation for Protein Chemical Synthesis

Protein chemical synthesis offers a promising strategy for ones to modify the protein with precision and flexibility for their biochemical and biophysical studies. Our group has developed a novel peptide ligation method utilizing N-terminal serine or threonine to mediate a chemoselective peptide ligation, termed serine/threonine ligation (STL). This method involves a chemoselective reaction between the peptide C-terminal salicylaldehyde esters and N-terminal Ser/Thr residues, followed by acidolysis to generate a native peptide linkage at the ligation junction. This chapter focuses on our work on the development of Ser/Thr ligation, including the preparation of peptide salicylaldehyde esters, development of the C-to-N and N-to-C strategies for sequential ligation, the compatibility study of one-pot Ser/Thr ligation and NCL, and the solubility issues under Ser/Thr ligation conditions. Other novel ligation strategies developed based on the concept of Ser/Thr ligation are also included herein.