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Publication Abstract from PubMed

Many peptide hormones adopt long alpha-helical structures upon interacting with their cognate receptors but often exhibit flexible conformations when unbound. Strategies that can stabilize long alpha-helices without disrupting their binding to receptors are still lacking, which hinders progress in their biological applications and drug development. Here, we present an approach that combines rational design with library screening to create and identify a unique disulfide-directed multicyclic peptide (DDMP) scaffold, which could effectively stabilize N-terminally extendable alpha-helices while displaying exceptional efficiency in disulfide pairing and oxidative folding. This DDMP scaffold was then utilized for stabilizing the alpha-helical structure of glucagon-like peptide-1 (GLP-1), resulting in a potent GLP-1 receptor (GLP-1R) agonist with a significantly improved alpha-helicity and proteolytic stability. By incorporating external alpha-helices into the DDMP scaffold, we can effectively preserve the native N-terminal alpha-helical structures while allowing for extensive evolution of the C-terminal disulfide-rich domain for enhancing target binding, as demonstrated by the generation of the DDMP-stabilized GLP-1 (g1:Ox). The cryo-electron microscopy structure of the g1:Ox-GLP-1R in complex with heterotrimeric G(s) reveals the molecular basis for the potent binding between g1:Ox and GLP-1R. Specifically, the DDMP moiety establishes additional interactions with the extracellular domain of GLP-1R, which are absent in the case of GLP-1. Thus, this work offers a novel and effective approach for engineering therapeutic peptides and other peptide alpha-helices, ensuring that both the N- and C-terminal regions remain essential for target recognition and activation.

Disulfide-Directed Multicyclic Peptides with N-Terminally Extendable alpha-Helices for Recognition and Activation of G Protein-Coupled Receptors.,Fan S, Li J, Zhuang J, Zhou Q, Mai Y, Lin B, Wang MW, Wu C J Am Chem Soc. 2025 Feb 12;147(6):4821-4832. doi: 10.1021/jacs.4c12808. Epub 2024 , Dec 17. PMID:39688263^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.