These tails are topic to a number of post-translational covalent modifications, including acetylation, phosphorylation, ubiquitination, sumoylation and methylation (reviewed in 1 ). Methylation been discovered on a spread of lysine residues in numerous histones: K4 (utilizing the one-letter amino-acid code for lysine), K9, K27, K36 and K79 in histone H3, K20 in histone H4, K59 in the globular area of histone H4 2 and K26 of histone H1B 3 Several proteins accountable for the methylation of particular residues have been characterised, and all but one in every of these comprises a SET area