Multiple Structural Clustering of Bromodomains of the Bromo and Extra Terminal (BET) Proteins Highlights Subtle Differences in Their Structural Dynamics and Acetylated Leucine Binding Pocket

BET proteins are epigenetic readers whose deregulation results in cancer and inflammation. We show that BET proteins (BRD2, BRD3, BRD4 and BRDT) are globally similar with subtle differences in the sequences and structures of their N-terminal bromodomain. Principal component analysis and nonnegative matrix factorization reveal distinct structural clusters associated with specific BET family members, experimental methods, and source organisms. Subtle variations in structural dynamics are evident in the acetylated lysine (Kac) binding pocket of BET bromodomains. Using multiple structural clustering methods, we have also identified representative structures of BET proteins, which are potentially useful for developing potential therapeutic agents.