These tails are topic to a number of publish-translational covalent modifications, including acetylation, phosphorylation, ubiquitination, sumoylation and methylation (reviewed lawyer in my area 1 ). Methylation been found on a range of lysine residues in numerous histones: K4 (using the only-letter amino-acid code for lysine), K9, K27, K36 and K79 in histone H3, K20 in histone H4, K59 in the globular domain of histone H4 2 and K26 of histone H1B 3 A number of proteins responsible for the methylation of particular residues have been characterised, and all however one in all these comprises a SET domain