Genetically Encoded Fragment-Based Discovery from Phage-Displayed Macrocyclic Libraries with Genetically Encoded...

Area of Science:

• Biochemistry
• Organic Chemistry
• Molecular Biology

Background:

• Genetically encoded macrocyclic peptide libraries are crucial for discovering ligands.
• Traditional methods involve early incorporation of unnatural building blocks.
• A need exists for more versatile library generation techniques.

Purpose of the Study:

• To develop a divergent late-stage approach for generating macrocyclic peptide libraries.
• To enable the incorporation of diverse pharmacophores into existing peptide libraries.
• To enhance the utility of genetically encoded libraries for molecular discovery.

Main Methods:

• Utilized a diketone linchpin (1,5-dichloropentane-2,4-dione) to convert phage-displayed peptide libraries into 1,3-diketone bearing macrocyclic peptides (DKMP).
• Employed Knorr pyrazole synthesis by ligating diverse hydrazine derivatives onto DKMP libraries.
• Incorporated silent DNA-barcodes for encoding both amino acid sequence and pharmacophore.

Main Results:

• Successfully generated macrocyclic libraries with DNA-encoded amino acid sequences and pharmacophores.
• Selection against carbonic anhydrase yielded macrocycles with benzenesulfonamide pharmacophore and nanomolar dissociation constants (Kd).
• Demonstrated the ability to graft diverse pharmacophores onto existing genetically encoded phage libraries.

Conclusions:

• The described late-stage methodology offers a powerful and flexible approach to macrocyclic peptide library generation.
• This technique significantly expands the scope and value of genetically encoded libraries for drug discovery and molecular recognition.
• The method facilitates the rapid discovery of high-affinity ligands for various biological targets.