Abstract
Nonproteinogenic amino acids, including d-α-, β-, and γ-amino acids, present in bioactive peptides play pivotal roles in their biochemical activities and proteolytic stabilities. d-α-Amino acids (dαAA) are widely used building blocks that can enhance the proteolytic stability. Cyclic β2,3-amino acids (cβAA), for instance, can fold peptides into rigid secondary structures, improving the binding affinity and proteolytic stability. Cyclic γ2,4-amino acids (cγAA) are recently highlighted as rigid residues capable of preventing the proteolysis of flanking residues. Simultaneous incorporation of all dαAA, cβAA, and cγAA into a peptide is expected to yield l-α/d-α/β/γ-hybrid peptides with improved stability and potency. Despite challenges in the ribosomal incorporation of multiple nonproteinogenic amino acids, our engineered tRNAPro1E2 successfully reaches such a difficulty. Here, we report the ribosomal synthesis of macrocyclic l-α/d-α/β/γ-hybrid peptide libraries and their application to in vitro selection against interferon gamma receptor 1 (IFNGR1). One of the resulting l-α/d-α/β/γ-hybrid peptides, IB1, exhibited remarkable inhibitory activity against the IFN-γ/IFNGR1 protein-protein interaction (PPI) (IC50 = 12 nM), primarily attributed to the presence of a cβAA in the sequence. Additionally, cγAAs and dαAAs in the resulting peptides contributed to their serum stability. Furthermore, our peptides effectively inhibit IFN-γ/IFNGR1 PPI at the cellular level (best IC50 = 0.75 μM). Altogether, our platform expands the chemical space available for exploring peptides with high activity and stability, thereby enhancing their potential for drug discovery.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.