Class I histone deacetylases including ScHos2 and SpPhd1
This subfamily includes Class I histone deacetylase (HDAC) Hos2 from Saccharomyces cerevisiae as well as a histone deacetylase Phd1 from Schizosaccharomyces pombe. Hos2 binds to the coding regions of genes during gene activation, specifically it deacetylates the lysines in H3 and H4 histone tails. It is preferentially associated with genes of high activity genome-wide and is shown to be necessary for efficient transcription. Thus, Hos2 is directly required for gene activation in contrast to other class I histone deacetylases. Protein encoded by phd1 is inhibited by trichostatin A (TSA), a specific inhibitor of histone deacetylase, and is involved in the meiotic cell cycle in S. pombe. Class 1 HDACs are Zn-dependent enzymes that catalyze hydrolysis of N(6)-acetyl-lysine residues in histone amino termini to yield a deacetylated histone (EC 3.5.1.98).
Comment:Active site includes Zn binding site, lipophilic tube and foot pocket.
Comment:Active site consists of a long narrow tunnel (that apparently serves for substrate binding) and a cavity with Zn ion (that is important for catalysis). In this structure, the tunnel is filled by the aliphatic chain of the inhibitor.
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