Histone acetyltransferase
（重定向自Histone acetyl transferase）
![Relative sizes and locations of important domains for representative HATs (HAT = catalytic acetyltransferase domain; Bromo = bromodomain; Chromo = chromodomain; Zn = zinc finger domain). The number of amino acid residues in each HAT is indicated at the right in each example.](/Images/godic/202501/18/Relative_sizes_and_locations_of_important_domains_for_representative_HATs5928.png")
![Crystal structure of Tetrahymena Gcn5 with bound coenzyme A and histone H3 peptide (PDB 1QSN). The central core (green), flanking N- and C-terminal segments (blue), coenzyme A (orange), and histone peptide (red) are shown.](/Images/godic/202501/18/Crystal_structure_of_Tetrahymena_Gcn5_with_bound_coenzyme_A_and_histone_H3_peptide5928.png")
![Catalytic mechanisms of GNAT and MYST family HATs. (A) General mechanism of GNAT HATs. (B) General mechanism of MYST HATs.](/Images/godic/202501/18/Catalytic_mechanisms_of_GNAT_and_MYST_family_HATs.5928.png")
![Schematic showing the role of HATs in gene transcription.](/Images/godic/202501/18/HAT_transcription5929.png")
Histone acetyltransferases (HATs) are enzymes that acetylate conserved lysine amino acids on histone proteins by transferring an acetyl group from acetyl CoA to form ε-N-acetyllysine. DNA is wrapped around histones, and, by transferring an acetyl group to the histones, genes can be turned on and off. In general, histone acetylation increases gene expression.