Computational Design, Synthesis, and Evaluation of Stapled Peptide-Based Antagonists of the CGRP Receptor

Hydrocarbon-stapled peptide antagonists targeting the calcitonin gene-related peptide (CGRP) receptor represent a promising strategy for migraine therapy. This study uses computational design tools and molecular dynamics simulations to develop novel stapled peptide antagonists conferring improved potency and stability compared to CGRP(8-37)-NH₂. Peptides with varied staple geometries and unnatural amino acids were assessed using circular dichroism and antagonism and serum stability assays. A stapled peptide (4), containing an S5/S5 i,i+4 hydrocarbon staple at positions 12 and 16, exhibited enhanced serum stability (compared to CGRP(8-37)-NH₂) and retained antagonist activity. Notably, Aib36-containing peptides (16-19) remained intact following prolonged serum stability exposure, but lost receptor antagonism. While the computational predictions of helicity and receptor binding largely corresponded to experimental outcomes, this trend was inconsistent, highlighting current in silico limitations. Moreover, this work advances the understanding of peptide structure-stability-activity trade-offs and informs future peptide therapeutic development, with particular implications for overcoming metabolic instability in peptide-based drugs.