Rational Design, Binding Studies, and Crystal‐Structure Evaluation of the First Ligand Targeting the Dimerization Interface of the 14‐3‐3ζ Adapter Protein

14-3-3 Proteins play a central role in signalling pathways in cells: they interact as gatekeeper proteins with a huge number of binding partners. Their function as hub for intracellular communication can explain why these adapter proteins are associated with a wide range of diseases. How they control the various cellular mechanisms is still unclear, but it is assumed that the dimeric nature of the 14-3-3 proteins plays a key role in their activity. Here, we present, to the best of our knowledge, the first example of a small molecule binding to the 14-3-3ζ dimerisation interface. This compound was designed by rational in silico optimisation of a peptidic ligand identified from biochemical screening of a peptidic library, and the binding was characterised by UV/Vis spectroscopy, microscale thermophoresis, multiscale simulations, and X-ray crystallography.