Acetylated Lysine

Acetyl is a functional group, the acyl with chemical formula CH3CO. It is sometimes represented by the symbol Ac. The acetyl group contains a methyl group single-bonded to a carbonyl. The carbonyl center of an acyl radical has one nonbonded electron with which it forms a chemical bond to the remainder R of the molecule. Histones and other proteins are often modified by acetylation. For example, on the DNA level, histone acetylation by acetyltransferases (HATs) causes an expansion of chromatin architecture, allowing for genetic transcription to occur. However, removal of the acetyl group by histone deacetylases (HDACs) condenses DNA structure, thereby preventing transcription.