Preparation of μSPOT Lactam-Cyclized Peptides for Ligand Optimization

Area of Science:

• Medicinal Chemistry
• Biotechnology
• Molecular Biology

Background:

• Cyclic peptides offer therapeutic potential for targeting protein-protein interactions (PPIs) due to their affinity, specificity, and stability.
• Developing effective cyclic peptide therapeutics requires efficient synthesis and screening methods.

Purpose of the Study:

• To develop a streamlined protocol for synthesizing and screening cyclic peptide libraries using side chain-to-side chain lactam cyclization.
• To explore cyclization positions and linker topology for optimizing cyclic peptide drug candidates.
• To identify cyclic peptide modulators of the amyloid precursor protein (APP)/Mint2 PPI, a target relevant to Alzheimer's disease.

Main Methods:

• Utilized the μSPOT method for peptide array synthesis and side chain-to-side chain lactam cyclization.
• Integrated orthogonal protection strategies and analytical controls for robust synthesis.
• Employed array-based binding assays for high-throughput screening and fluorescence polarization assays for validation.

Main Results:

• Successfully developed cyclic peptide modulators of the APP/Mint2 PPI.
• Demonstrated efficient synthesis and screening of cyclic peptide libraries with minimal synthetic effort.
• Showcased a strong correlation (r² = 0.88) between array-based binding data and fluorescence polarization assay results.

Conclusions:

• The described method provides a versatile and scalable platform for discovering novel cyclic peptides.
• The approach enhances stability, affinity, and permeability of cyclic peptides for therapeutic applications.
• This work facilitates the development of advanced therapeutics targeting challenging PPIs.