CHEMBL5738008

ATPLITE assay: Acetyl-Histone Binding Assay. Assays were performed as described previously with minor modifications from the manufacturer's protocol (PerkinElmer, USA). All reagents were diluted in 50 mM HEPES, 100 mM NaCl, 0.1% BSA, pH 7.4 supplemented with 0.05% CHAPS and allowed to equilibrate to room temperature prior to addition to plates. A 24-point 1:2 serial dilution of the ligands was prepared over the range of 150-0 μM and 4 μl transferred to low-volume 384-well plates (ProxiPlate™-384 Plus, PerkinElmer, USA), followed by 4 μl of HIS-tagged protein (BRD4/1, 250 nM, BRD4/2 and CREBBP, 2000 nM). Plates were scaled and incubated at room temperature for 30 minutes, before the addition of 4 μl of biotinylated peptide at equimolar concentration to the protein [peptide for BRD4(1) & BRD4(2), and BRDT: H4K5acK8acK12acK16ac, H-SGRGK(Ac)GGK(Ac)GLGK(Ac)GGAK(Ac)RHRK(Biotin)-OH; peptide for CREBBP: H3K36ac, Biotin-KSAPATGGVK(Ac)KPHRYRPGT-OH (Cambridge Research Biochemicals, UK)]. Plates were sealed and incubated for a further 30 minutes, before the addition of 4 μl of streptavidin-coated donor beads (25 μg/ml) and 4 μl nickel chelate acceptor beads (25 μg/ml) under low light conditions. Plates were foil-sealed to protect from light, incubated at room temperature for 60 minutes and read on a PHERAstar FS plate reader (BMG Labtech, Germany) using an AlphaScreen 680 excitation/570 emission filter set. IC50 values were calculated in Prism 5 (GraphPad Software, USA) after normalization against corresponding DMSO controls and are given as the final concentration of compound in the 20 μl reaction volume.