The TR-FRET PPAR (peroxisome proliferator activated receptor) delta Coactivator Assay Kit provides a sensitive and robust method for high-throughput screening of potential PPAR delta ligands as agonists of ligand-dependent coactivator recruitment. The kit uses a terbium (Tb)-labeled anti-GST antibody, a fluorescein-labeled coactivator peptide, and a human recombinant PPAR delta ligand-binding domain (PPAR delta-LBD) that is tagged with glutathione-S-transferase (GST), in a homogeneous mix-and-read assay format.
When running the TR-FRET PPAR delta Coactivator Assay in agonist mode (to identify agonist compounds), PPAR delta-LBD is added to ligand test compounds followed by addition of a mixture of the fluorescein-labeled coactivator peptide and Tb-labeled anti-GST antibody. After an incubation period at room temperature, the TR-FRET ratio of 520/495 is calculated and can be used to determine the EC50 from a dose response curve of the compound. Based on the biology of the PPAR delta-coactivator peptide interaction, this ligand EC50 is a composite value representing the amount of ligand required to bind to receptor, effect a conformational change, and recruit coactivator peptide.