Peptide Ligation

Ref: 12268
A novel ligation method for the synthesis of phosphopeptides and peptides, using serine or threonine residues to facilitate amide bond formation with a range of C-terminal thioesters.

Key advantages
  • Greater range of peptide coupling sites using serine and threonine
  • Phosphopeptides are synthesised in high yields
  • Phosphate group can be readily removed enzymatically after the ligation reaction to generate native peptides and proteins


Proposed mechanism of phosphate-assisted ligation.

Proposed mechanism of phosphate-assisted ligation.

Native Chemical Ligation is currently limited to protein fragments bearing an N-terminal cysteine residue. Cysteine is the second least abundant amino acid (1.7%) found in naturally occuring proteins and, as such, it is often difficult to find a suitable site for ligation within a protein sequence.

The ability to ligate peptides with N-terminal serine and threonine residues, with natural abundances of 7.4% and 5.8% respectively, will greatly enhance the ability to synthesise proteins that can not currently be produced by native chemical ligation.

There is also a need for efficient methods for the synthesis of post-translationally modified peptides and proteins which form an important class of biologically active molecules.

Current recombinant protein expression systems usually display a heterogeneous display of the post-translational modification (phosphate, carbohydrate) in the final product. This technology will allow greater control over the synthesis of the desired peptides/proteins or post-translationally modified peptides/proteins.

The invention

This invention is an efficient, high yielding method for the convergent ligation-based assembly of peptides and phosphopeptides. This technolgoy will allow for the synthesis of native peptides and phosphopeptides. The combined natural abundance of serine and threonine of 13.2% creates a wealth of opportunities in the field of peptide and protein synthesis, not previously available using the cysteine-based native chemical ligation platform.


Increased range of ligation sites for the convergent ligation-based assembly of peptides, proteins, phosphopeptides and phosphoproteins. Phosphopeptides products can be used as therapeutic leads. Potential applications include the controlled synthesis of glycoprotein drugs such as erythropoietin (EPO).

Principal inventors

  • Dr Richard Payne
  • Gemma Thomas