Discovery of a PCAF Bromodomain Chemical Probe. (14th December 2016) - Moustakim, Moses
Abstract: The p300/CBP‐associated factor (PCAF) and related GCN5 bromodomain‐containing lysine acetyl transferases are members of subfamily I of the bromodomain phylogenetic tree. Iterative cycles of rational inhibitor design and biophysical characterization led to the discovery of the triazolopthalazine‐based L‐45 (dubbed L‐Moses ) as the first potent, selective, and cell‐active PCAF bromodomain (Brd) inhibitor. Synthesis from readily available (1R, 2S)‐(−)‐norephedrine furnished L‐45 in enantiopure form. L‐45 was shown to disrupt PCAF‐Brd histone H3.3 interaction in cells using a nanoBRET assay, and a co‐crystal structure of L‐45 with the homologous Brd PfGCN5 from Plasmodium falciparum rationalizes the high selectivity for PCAF and GCN5 bromodomains. Compound L‐45 shows no observable cytotoxicity in peripheral blood mononuclear cells (PBMC), good cell‐permeability, and metabolic stability in human and mouse liver microsomes, supporting its potential for in vivo use. Abstract : Inhibitor per Design : Der erste potente, selektive und zellaktive Inhibitor der PCAF‐Bromodomänen (Brd) wird beschrieben. Durch einen nanoBRET‐Assay wurde nachgewiesen, dass L ‐Moses die PCAF‐Brd/Histon‐H3.3‐Wechselwirkung in Zellen unterbricht, und eine Kokristallstruktur von L ‐Moses mit der homologen Brd PfGCN5 hilft, die hohe Selektivität für PCAF‐ und GCN5‐Bromodomänen zu erklären.