A facile method to screen inhibitors of protein–protein interactions including MDM2–p53 displayed on T7 phage

Protein–protein interactions are essential in many biological processes including cell cycle and apoptosis. It is currently of great medical interest to inhibit specific protein–protein interactions in order to treat a variety of disease states. Here, we describe a facile multiwell plate assay method using T7 phage display to screen for candidate inhibitors of protein–protein interactions. Because T7 phage display is an effective method for detecting protein–protein interactions, we aimed to utilize this technique to screen for small-molecule inhibitors that disrupt these types of interaction. We used the well-characterized interaction between p53 and MDM2 and an inhibitor of this interaction, nutlin 3, as a model system to establish a new screening method. Phage particles displaying p53 interacted with GST–MDM2 immobilized on 96-well plates, and the interaction was inhibited by nutlin 3. Multiwell plate assay was then performed using a natural product library, which identified dehydroaltenusin as a candidate inhibitor of the p53–MDM2 interaction. We discuss the potential applications of this novel T7 phage display methodology, which we propose to call ‘reverse phage display’.