Structural Basis of Small-Molecule Aggregate Induced Inhibition of a Protein–Protein Interaction

A prevalent observation in high-throughput screening and drug discovery programs is the inhibition of protein function by small-molecule compound aggregation. Here, we present the X-ray structural description of aggregation-based inhibition of a protein–protein interaction involving tumor necrosis factor α (TNFα). An ordered conglomerate of an aggregating small-molecule inhibitor (JNJ525) induces a quaternary structure switch of TNFα that inhibits the protein–protein interaction between TNFα and TNFα receptors. SPD-304 may employ a similar mechanism of inhibition.