Interrogating Substrate Selectivity and Composition of Endogenous Histone Deacetylase Complexes with Chemical Probes.

Histone deacetylases (HDACs) regulate the function and activity of numerous cellular proteins by removing acetylation marks from regulatory lysine residues. We have developed peptide-based HDAC probes that contain hydroxamate amino acids of various lengths to replace modified lysine residues in the context of known acetylation sites. The interaction profiles of all human HDACs were studied with three sets of probes, which derived from different acetylation sites, and sequence context was found to have a strong impact on substrate recognition and composition of HDAC complexes. By investigating K382 acetylation of the tumor suppressor p53 as an example, we further demonstrate that the interaction profiles reflect the catalytic activities of respective HDACs. These results underline the utility of the newly established probes for deciphering not only activity, but also substrate selectivity and composition of endogenous HDAC complexes, which can hardly be achieved otherwise.