Selective thiazoline peptide cyclisation compatible with mRNA display and efficient synthesis.

Area of Science:

• Biochemistry
• Molecular Biology
• Medicinal Chemistry

Background:

• Linear peptides often lack stability in biological systems, limiting their therapeutic potential.
• Macrocyclization improves peptide affinity, selectivity, stability, and cell permeability.
• Genetically encoding macrocyclization during peptide discovery is advantageous over post-discovery methods.

Purpose of the Study:

• To introduce a novel method for genetically encoding macrocyclization in peptides using meta-cyanopyridylalanine (mCNP).
• To demonstrate the utility of mCNP for creating stable macrocyclic and bicyclic peptides.
• To explore the application of this technology in discovering bioactive peptide sequences.

Main Methods:

• Ribosomal incorporation of mCNP into peptides during translation.
• Spontaneous macrocyclization via reaction between mCNP and N-terminal cysteine.
• Incorporation of mCNP during Fmoc solid-phase peptide synthesis.
• Discovery of macrocyclic peptides targeting influenza haemagglutinin.
• Molecular dynamics simulations to analyze structural stabilization.
• Compatibility studies with thioether macrocyclization for bicyclic peptide formation.

Main Results:

• mCNP is successfully incorporated into peptides and spontaneously forms macrocycles with N-terminal cysteine.
• The mCNP cross-link stabilizes beta-sheet structures in bioactive macrocyclic peptides.
• The method allows for controlled formation of bicyclic peptides through sequential macrocyclizations.
• mCNP incorporation is compatible with standard peptide synthesis techniques.

Conclusions:

• mCNP provides a versatile and genetically encoded approach for peptide macrocyclization.
• This technology enhances peptide stability and structural rigidity, improving their drug-like properties.
• The method facilitates the discovery and development of novel macrocyclic and bicyclic peptide therapeutics.