Optimal Stapling of a Helical Peptide‐Foldamer Hybrid Using a C‐Terminal 4‐Mercaptoproline Enhances Protein Surface Recognition and Cellular Activity

• DOI: 10.1002/chem.202403330
• Publication Date: 2025-03-11T13:55:55Z
• Authors: Maxime Neuville; Mathieu Bourgeais; Jérémie Buratto; Claire Saragaglia; Bo Li; Isabel Galeano‐Otero; Laura Mauran; Laetitia Varajao; Sébastien R. Goud...; Brice Kauffmann; Emmanuelle Thinon; Morgane Pasco; Abdel‐Majid Khatib; Gilles Guichard

AbstractStructural analysis of a co‐crystal of a helically‐folded peptide‐foldamer hybrid in complex with hDM2 E3 ubiquitin ligase, revealed a unique orientation for the C‐terminal proline with the pyrrolidine ring pointing backwards in the sequence, and suggested new opportunities for macrocyclization. In particular, we found that the C‐terminal prolyl residue could be replaced by its (2S,4S)‐4‐mercaptoprolyl analogue for optimal bisthioether crosslinking with a cysteine residue installed at position 4 in the sequence. The resulting i,i+7 stapled peptide‐foldamer is a high‐affinity binder to hDM2, is cell permeable and restores the p53 signalling pathway in p53wt cancer cells. The co‐crystal structure of hDM2 and the stapled peptide‐foldamer hybrid was determined at 1.84 Å, fully validating the original design and further highlighting the potential of cis‐4‐mercaptoproline in the context of peptide and foldamer stapling.