Expanding the Chemical Space of Mechanically Interlocked Peptides (MIPs) via Rational Design and Metabolite Profiling

Area of Science:

• Chemical Biology
• Supramolecular Chemistry
• Medicinal Chemistry

Background:

• Mechanically interlocked peptides (MIPs) exhibit superior biological stability, presenting a promising avenue for therapeutic applications.
• Current limitations exist in the accessible chemical space and practical methodologies for designing and synthesizing MIPs, particularly for conventional linear peptides.

Purpose of the Study:

• To develop a robust and broadly applicable strategy for the mechanical interlocking and stabilization of peptides.
• To establish design guidelines for MIP construction and expand their chemical space.
• To investigate the mechanistic basis of mechanical stabilization and its impact on peptide degradation.

Main Methods:

• Utilized active-template Cu-(I)-catalyzed azide-alkyne cycloaddition (AT-CuAAC) for peptide interlocking.
• Systematically explored parameters including amino acid side chains, macrocycle size, peptide length, and reaction conditions.
• Applied the methodology to longer peptide sequences, such as [Y]6-AngII, using convergent and iterative assembly routes.

Main Results:

• A diverse library of interlocked short peptides was constructed, alongside design guidelines.
• The AT-CuAAC strategy was successfully applied to longer peptide sequences, demonstrating broad applicability.
• Interlocked peptides showed exceptional stability in biological fluids, maintaining >95% integrity in plasma (48h) and 20% in whole blood (24h).
• Metabolite profiling indicated that the mechanical bond shields at least 8 contiguous residues from degradation.

Conclusions:

• The developed AT-CuAAC approach provides a robust and versatile method for constructing MIPs.
• This work offers critical insights into the mechanism of mechanical stabilization in peptides.
• The findings expand the available tools for designing highly stable peptide therapeutics.