Bromodomain: an acetyl-lysine binding domain.

Bromodomains, an extensive family of evolutionarily conserved protein modules originally found in proteins associated with chromatin and in nearly all nuclear histone acetyltransferases, have been recently discovered to function as acetyl-lysine binding domains. More recent structural studies of bromodomain/peptide ligand complexes have enriched our understanding of differences in ligand selectivity of bromodomains. These new findings demonstrate that bromodomain/acetyl-lysine recognition can serve as a pivotal mechanism for regulating protein-protein interactions in numerous cellular processes including chromatin remodeling and transcriptional activation, and reinforce the concept that functional diversity of a conserved protein modular structure is achieved by evolutionary changes of amino acid sequences in the ligand binding site.