Assay Method Information

Assay Name:  Binding Assay
Description:  Compounds of the present invention were tested for ability to bind to RORγ in a cell-free competition assay with commercially available radio-ligand (RL), 25-hydroxy [26,27-3H]-cholesterol (PerkinElmer, Cat. #NET674250UC), for a ligand binding site on a recombinant RORγ Ligand Binding Domain (LBD) protein expressed as a 6×His-Glutathione-S-Transferase (GST) fusion. The assay was performed in 96-well SPA plates (PerkinElmer, Cat. #1450-401) in 50 mM HEPES buffer, pH 7.4, containing 150 mM NaCl, 5 mM MgCl2, 10% (v/v) glycerol, 2 mM CHAPS, 0.5 mM β-octylglucopyranoside and 5 mM DTT. Tested compounds were dissolved in DMSO, and semi-log (3.162×) serial dilutions of the compounds were prepared in the same solvent. Two μL of the DMSO solutions were mixed with 28 μL of 8.6 nM 25-hydroxy [26,27-3H]-cholesterol and 50 μL of 24 nM RORγ LBD. The plate was shaken at 700 rpm for 20 min and incubated for 10 min at rt, after which 40 μL of poly-Lys YSi SPA beads (PerkinElmer, Cat. #RPNQ0010) were added to achieve 50 μg of the beads per well. The plate was incubated on an orbital shaker for 20 min and then for 10 min without agitation at rt. SPA signal for tritium beta radiation was registered on PerkinElmer Microbeta plate reader. Percent inhibition values were calculated based on the high signal obtained with DMSO control and the low signal observed with 10 μM standard RORγ inverse agonist T0901317 (SigmaAldrich, Cat. #T2320). The percent inhibition vs. concentration data were fit into a four-parameter model, and IC50 values were calculated from the fit as the concentrations corresponding to the inflection points on the dose-response curves.
Affinity data for this assay

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