Assay Report Card

ID: ALA3888180

Type: Binding

Description: Homogenous Time-Resolved Fluorescence Assay (HTRF2 Assay): The standard assay conditions for the in vitro HTRF assay consisted of a 50 ul total reaction volume in black 384-well Costar polypropylene plates in 1xPBS buffer pH 7.4, 1 mM DTT, 0.1% BSA, 0.2 nM GST-hMDM2 (aa 1-188), 0.5 nM biotinylated-p53 (aa 1-83), 0.18 nM SA-XLent (Cisbio; Bedford, Mass.), 0.6 nM anti-GST cryptate monoclonal antibody (Cisbio; Bedford, Mass.) and 100 mM KF. Amino acid residues 1-188 of human MDM2 were expressed as an amino-terminal glutathione-5-transferase (GST) fusion protein (GST-hMDM2) in Escherichia coli. Residues 1-83 of human p53 were expressed as an amino-terminal AviTag-TrxA-6×His fusion protein (biotinylated p53) in E. coli. Each protein was purified from cell paste by affinity chromatography. Specifically, 10 uL of GST-hMDM2 was incubated with 10 ul of diluted compound (various concentrations, serially diluted) in 10% DMSO for 20 minutes at room temperature. 20 uL of biotinylated-p53 was added to the GST-hMDM2+compound mixture, and then incubated at room temperature for 60 min. 10 uL of detection buffer consisting of SA-XLent, anti-GST cryptate antibody and KF was added to GST-hMDM2, biotinylated-p53 and compound reaction and left at room temperature to reach equilibrium for >4 hrs. The final concentration of DMSO in the reaction was 2%. Time-resolved fluorescence readings were measured on a microplate multilabel reader. Percentage of inhibition was calculated relative to nutlin-3.