Discovery of IL-5-binding unnatural cyclic peptides from multiple libraries by directed evolution

Interleukin-5 (IL-5) is a type 2 cytokine involved in various allergic diseases, including severe eosino-philic asthma. In this study, we performed directed evolution against human IL-5 using systematic evolution of ligands by exponential enrichment (SELEX) from multiple mRNA-displayed peptide libraries. Peptide libraries were prepared with Escherichia coli-based reconstituted cell-free transcription and translation coupling system (PURE system) and spontaneously cyclized using multiple intramolecularly thiol-reactive benzoic acid-derived linkers, which were ribosomally incorporated through genetic code expansion. We successfully identified multiple novel IL-5-binding unnatural cyclic peptides with different cyclization linkers from multiple highly diverse mRNA-displayed libraries. Chemical dimer-ization was also performed to increase the avidity of unnatural cyclic IL-5-binding peptides. The novel IL-5-binding unnatural cyclic peptides discovered in this study could be used in various research, thera-peutic, and diagnostic applications involving IL-5 signaling. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

In this study, directed evolution was performed on human IL-5 using SELEX to discover novel IL-5-binding unnatural cyclic peptides. These peptides can be utilized in various research, therapeutic, and diagnostic applications involving IL-5 signaling.