Enzyme-catalyzed macrocyclization of long unprotected peptides

Area of Science:

• Biochemistry
• Synthetic Chemistry
• Peptide Science

Background:

• Peptide macrocyclization is crucial for drug discovery and biological studies.
• Existing methods for peptide macrocyclization can be complex and low-yielding.

Purpose of the Study:

• To develop a novel, efficient method for peptide macrocyclization using glutathione S-transferase (GST).
• To demonstrate the synthesis of large peptide macrocycles by combining GST-catalyzed ligation with native chemical ligation.

Main Methods:

• Utilized glutathione S-transferase (GST) to catalyze a selective S(N)Ar reaction.
• Employed an N-terminal glutathione (GSH) tag and a C-terminal perfluoroaryl-modified cysteine for cyclization.
• Combined GST-catalyzed ligation with native chemical ligation for synthesizing larger macrocycles.

Main Results:

• Achieved quantitative production of cyclic peptides (9-24 residues) within 2 hours.
• Demonstrated high selectivity for cyclization at the GSH tag.
• Successfully generated a 40-amino acid peptide macrocycle by combining ligation strategies.

Conclusions:

• GST-catalyzed macrocyclization offers a rapid and efficient route to cyclic peptides.
• This method is versatile and scalable for producing complex peptide structures.
• The combined approach expands possibilities in peptide synthesis and engineering.