Ki: 30-50 nM (BRD4 bromodomain)
MS436, through a set of water-mediated interactions, exhibits low nanomolar affinity (estimated K i of 30-50 nM) with preference for the first bromodomain over the second. MS436 effectively inhibits BRD4 activity in NF-κB-directed production of NO and pro-inflammatory cytokine interleukin-6 in murine macrophages. MS436 represents a new class of bromodomain inhibitors and will facilitate further investigation of the biological functions of the two bromodomains of BRD4 in gene expression. MS436 exhibits potent affinity of an estimated K i =30-50 nM for the BRD4 BrD1 and a 10-fold selectivity over the BrD2, which is achieved through a unique set of water-mediated intermolecular interactions.