Inhibition of Aurora‐A/N‐Myc Protein–Protein Interaction Using Peptidomimetics: Understanding the Role of Peptide Cyclization

Using N‐Myc_61‐89 as a starting template we showcase the systematic use of truncation and maleimide constraining to develop peptidomimetic inhibitors of the N‐Myc/Aurora‐A protein–protein interaction (PPI); a potential anticancer drug discovery target. The most promising of these – N‐Myc_{73‐94‐N85C/G89C‐mal} – is shown to favour a more Aurora‐A compliant binding ensemble in comparison to the linear wild‐type sequence as observed through fluorescence anisotropy competition assays, circular dichroism (CD) and nuclear magnetic resonance (NMR) experiments. Further in silico investigation of this peptide in its Aurora‐A bound state, by molecular dynamics (MD) simulations, imply (i) the bound conformation is more stable as a consequence of the constraint, which likely suppresses dissociation and (ii) the constraint may make further stabilizing interactions with the Aurora‐A surface. Taken together this work unveils the first orthosteric N‐Myc/Aurora‐A inhibitor and provides useful insights on the biophysical properties and thus design of constrained peptides, an attractive therapeutic modality.