Targeting intracellular protein–protein interactions with cell-permeable cyclic peptides

Intracellular protein–protein interactions (PPIs) are challenging targets for conventional drug modalities, because small molecules generally do not bind to their large, flat binding sites with high affinity, whereas monoclonal antibodies cannot cross the cell membrane to reach the targets. Cyclic peptides in the 700–2000 molecular-weight range have the sufficient size and a balanced conformational flexibility/rigidity for binding to flat PPI...