Histone Acetylation

Histone acetylation is a post-translational modification involving the addition of an acetyl group (COCH₃) from acetyl coenzyme A with the use of enzymes called histone acetyltransferases ⁽¹⁾. These enzymes catalayse the addition of an acetyl group on to lysine residues in areas which are usually promoter regions, such as H3 and H4 ⁽²⁾. As lysine is postively charged and DNA is negatively charged they bind together keeping the structure compact, however with the addition of a positvely charged acetylation the structure becomes less compact thus revealing promoter regions for transcription to occur ⁽²⁾. Acetyl groups can be removed from lysine residues in a hydrolytic process using histone deactylases. The acetylation of histones is involved in many cellular processes ⁽¹⁾.

References:

1) What is Epigenetics. Histone Modifications. Accessed 01/12/16

http://www.whatisepigenetics.com/histone-modifications/

2) Epigenetics. Histone Modifications. Accessed 01/12/16

http://www.abcam.com/epigenetics/histone-modifications-a-guide