Figure 3.

Catalytic action of HDACs. (A) Proposed mechanism of acetyl-lysine hydrolysis catalyzed by HDACs. (B) Sequence conservation of four regions containing the key catalytic amino acids (red asterisks) between all HDACs of the model species used for the phylogenetic tree in Figure 1. Residue Y345 is replaced by an H only in vertebrate Class IIa HDACs.