Chemical and structural lessons from recent successes in protein-protein interaction inhibition (2P2I)

Worldwide research efforts have driven recent pharmaceutical successes, and consequently, the emerging role of Protein-Protein Interactions (PPIs) as drug targets has finally been widely embraced by the scientific community. Inhibitors of these Protein-Protein Interactions (2P2Is or i-PPIs) are likely to represent the next generation of highly innovative drugs that will reach the market over the next decade. This review describes up-to-date knowledge on this particular chemical space, with a specific emphasis on a subset of this ensemble. We also address current structural knowledge regarding both protein-protein and protein-inhibitor complexes, that is, the 2P2I database. Finally, ligand efficiency analyses permit us to relate potency to size and polarity and to discuss the need to co-develop nanoparticle drug delivery systems.