Fluorescence polarization for the evaluation of small-molecule inhibitors of PCAF BRD/Tat-AcK50 association.

A fluorescence polarization competitive assay was developed to efficiently screen and evaluate inhibitors of PCAF bromodomain/Tat-AcK50 protein-peptide interaction. A series of pyridine 1-oxide derivatives were synthesized and evaluated. Some of the novel compounds, 2-(3-aminopropylamino) pyridine 1-oxide derivatives, could be effective inhibitors of PCAF bromodomain/Tat-AcK50 association. Specifically, 2-(3-aminopropylamino)-5-(hydroxymethyl)pyridine 1-oxide hydrochloride (15) and the 5-((3-aminopropylamino)methyl) derivative (20) were found to be effective ligands for the PCAF BRD pocket. First preliminary cellular studies indicate that these small-molecule inhibitors have lower cytotoxicities and are potential leads for the anti-HIV/AIDS therapeutic strategy by targeting host-cell protein PCAF BRD to block HIV replication.