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.
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.
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).
- Dr Richard Payne
- Gemma Thomas