Cys-Lys stapling for unprotected peptides via tunable linkers.

Area of Science:

• Peptide Chemistry
• Chemical Biology
• Medicinal Chemistry

Background:

• Peptide stapling enhances peptide properties but non-symmetric methods face synthetic challenges.
• Achieving chemoselectivity and site selectivity in unprotected peptides is difficult.

Purpose of the Study:

• To develop a non-symmetric stapling strategy for cysteine-lysine crosslinking in peptides and proteins.
• To create tunable linkers for macrocyclization under physiological conditions.

Main Methods:

• Developed unsymmetrically tunable linkers for selective cysteine-lysine ligation.
• Established a library of 17 stapling reagents with varied properties.
• Facilitated macrocyclization of peptide loops into 25-40-membered rings.

Main Results:

• Achieved high chemoselectivity and regioselectivity in non-symmetric stapling.
• Demonstrated successful macrocyclization of intervening loops under physiological conditions.
• Conformationally restricted peptides showed increased alpha-helicity, stability, and anti-bladder cancer activity.

Conclusions:

• The developed non-symmetric stapling protocol offers a versatile approach for peptide and protein modification.
• This method enhances peptide biophysical properties and therapeutic potential, particularly for cancer treatment.
• The tunable linker library facilitates drug discovery and development through precise conformational control.