Overall Shape Constraint of Alternating α/β-Hybrid Peptides Containing Bicyclic β‑Proline

Our NMR, IR/Raman, CD spectroscopic, and X-ray crystallographic studies, as well as accelerated molecular dynamics simulations, showed that alternating hybrid α/β-peptides containing a bicyclic β-proline surrogate form unique extended curved folds, regardless of the peptide length and solvent environment. It is suggested that extended β/PPII structures are preferred in the insulating α-alanine moieties between the rigid bicyclic β-proline structures. These hybrid peptides inhibit p53-MDM2 and p53-MDMX protein–protein interactions.