Thioester Ligation with AAHO Peptides.

Area of Science:

• Organic Chemistry
• Biochemistry
• Synthetic Chemistry

Background:

• Peptide synthesis is crucial for developing therapeutics and understanding biological processes.
• Existing peptide ligation methods often face challenges with efficiency, side reactions, or auxiliary removal.
• The development of new ligation strategies is essential for advancing peptide-based research and applications.

Purpose of the Study:

• To introduce a novel chemoselective ligation reaction for peptide synthesis.
• To utilize aminoacyl-N-hydroxy peptides (AAHO peptides) in a ligation strategy.
• To demonstrate the utility of this method for complex peptide modifications, such as ubiquitination.

Main Methods:

• A new ligation reaction between peptide thioesters and AAHO peptides was developed.
• The reaction proceeds via a thio-to-oxo transesterification forming an O-acyl intermediate.
• Reductive cleavage was employed for the removal of the N-hydroxyl auxiliary.

Main Results:

• A highly chemoselective ligation reaction forming native peptide bonds was achieved.
• The N-hydroxyl auxiliary was efficiently removed post-ligation.
• The method was successfully applied to the ubiquitination of a synthetic peptide containing an AAHO-modified lysine residue.

Conclusions:

• The reported ligation strategy offers a new and efficient method for native peptide bond formation.
• The facile removal of the N-hydroxyl group simplifies subsequent peptide modifications.
• This approach holds promise for the synthesis of complex peptides and peptidomimetics, including ubiquitinated proteins.