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

Abstract

Using N‐Myc61‐89 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‐Myc73‐94‐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.

Exploring the dynamics and interactions of the N-myc transactivation domain through solution NMR

“…5A). Peptides were synthesized for Pro45–Leu61 (MBI); Glu73–Gly89, the region that appears as a helix in the N-myc–Aurora-A crystal structure [31] or ‘Aurora-A-interacting helix’ (AIH) [78]; and Gly119–Gln135, a region with helical propensity that extends beyond MBII…”

“…S8E). The interaction with Aurora-A can be reinforced using helix-constrained N-myc AIH peptides [78], suggesting that a level of pre-organization can facilitate binding. Although there is limited sequence identity between N-myc and c-myc in the region after MBI, c-myc, in a similar position to the N-myc AIH, has been crystallised interacting as a helix with the TBP–TAF1 complex (c-myc 97–107) [30].…”