| Assay Method Information | |
| | Radio-Ligand RORgamma Binding Assay (Assay 1) |
| 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 (3.162x) 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 mM and incubated for 10 mM 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 mM and then for 10 mM 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. Inhibitory constants (Ki) were calculated using the following equation, where [RL] is the concentration in the assay and KD is a dissociation constant of 25-hydroxy [26,27-3H]-cholesterol:K i = IC 50 ( 1 + [ RL ] K D ) . |
| Affinity data for this assay | |
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