Stapled β-Hairpins Featuring 4-Mercaptoproline

Area of Science:

• Biochemistry
• Medicinal Chemistry
• Computational Chemistry

Background:

• Stapled alpha-helices are established scaffolds in drug development.
• Constrained scaffolds for other secondary structures, like beta-strands, are less explored.
• Developing novel peptide scaffolds is crucial for expanding therapeutic options.

Purpose of the Study:

• To computationally design an optimal staple for antiparallel beta-strands.
• To synthesize and characterize beta-hairpin peptides incorporating this novel staple.
• To evaluate the potential of these stapled peptides as inhibitors of protein-protein interactions.

Main Methods:

• Utilized a novel computational strategy to identify an optimal staple design.
• Incorporated the designed staple into a beta-hairpin peptide sequence.
• Employed biophysical methods to assess structural stability in aqueous solution and resistance to degradation in cell lysates.
• Measured cellular penetration at micromolar concentrations.
• Analyzed structural overlay with protein-protein interaction interfaces.

Main Results:

• Successfully identified an optimal staple for antiparallel beta-strands.
• Developed stapled beta-hairpin peptides featuring a unique, kinked structure due to 4-mercaptoproline.
• Demonstrated high structural integrity in aqueous solution.
• Exhibited excellent resistance to degradation in cell lysates.
• Achieved cytosolic penetration at micromolar concentrations.
• Identified structural similarities with kinked hairpin motifs at protein-protein interaction interfaces.

Conclusions:

• Novel stapled beta-hairpin peptides exhibit promising structural and cellular properties.
• These scaffolds represent a new class of constrained peptides for drug development.
• The developed stapled hairpins are potential starting points for designing inhibitors of cellular protein-protein interactions.