Abstract: The present disclosure provides a method of determining resistance of a biological molecule to inhibition of its interaction with a target molecule by an inhibitor of the biological molecule, the method comprising the steps of: a) co-compartmentalizing a gene encoding the biological molecule with the target molecule, or a gene encoding the biological molecule with a gene encoding the target molecule into an aqueous droplet disposed within a water-in-oil emulsion, and b) assaying for a complex comprising the biological molecule and the target molecule upon expression of the gene encoding the biological molecule and the gene encoding the target molecule, wherein detection of the complex in the presence of the inhibitor indicates that the biological molecule is resistant to inhibition of its interaction with the target molecule by the inhibitor. Also provided are mutated HDM2 ubiquitin ligase polypeptides exhibiting resistance to Nutlin inhibition of p53 binding.

Abstract: By using a phage display derived peptide as an initial template, compounds have been developed that are highly specific against Mdm2/Mdm4. These compounds exhibit greater potency in p53 activation and protein-protein interaction assays than a compound derived from the p53 wild-type sequence. Unlike nutlin, a small molecule inhibitor of Mdm2/Mdm4, the phage derived compounds can arrest cells resistant to p53 induced apoptosis over a wide concentration range without cellular toxicity, suggesting they are highly suitable for cyclotherapy.