Proteins of the Rpd3-like family are class I Zn-dependent Histone deacetylases that catalyze hydrolysis of an N(6)-acetyl-lysine residue of a histone to yield a deacetylated histone (EC 3.5.1.98). RPD3 is the yeast homolog of class I HDACs. The main function of RPD3-like group members is regulation of a number of different processes through protein (mostly different histones) modification (deacetylation). This group includes fungal RPD3 and acts via the formation of large multiprotein complexes. Members of this group are involved in cell cycle regulation, DNA damage response, embryonic development and cytokine signaling important for immune response. Histone deacetylation by yeast RPD3 represses genes regulated by the Ash1 and Ume6 DNA-binding proteins. In mammals, they are known to be involved in progression of various tumors. Specific inhibitors of mammalian histone deacetylases could be a therapeutic drug option.
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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