ADD: The ADD domain of the DNMT3a DNA methyltransferase has been shown to interact with H4R3me2s, promoting silencing of the human β-globin locus. (1)
Reference
1. Musselman CA, Lalonde ME, Cote J, Kutateladze TG.Perceiving the epigenetic landscape through histone readers. Nat Struct Mol Biol.2012;19(12):1218-27. PMID: 23211769.
BAH: Owing to extensive intermolecular contacts, the ankyrin repeats of G9a and GLP and the BAH domain of ORC1 show high specificity for di- or monomethylated H3K9 and H4K20me2, respectively. The H3K9me2 peptide is sandwiched between the β-turns and α-helices of the fourth and fifth ankyrin repeats, whereas K9me2 fits into the aromatic cage also containing a glutamate. (1)
Reference
1. Musselman CA, Lalonde ME, Cote J, Kutateladze TG.Perceiving the epigenetic landscape through histone readers. Nat Struct Mol Biol.2012;19(12):1218-27. PMID: 23211769.
Chromo-Barrel: Chromo-Barrel, as the other member of the Royal family, shows some specificity, preferring tri- or dimethylated H3K36 and monomethylated H4K20 (H4K20me1); however, they bind rather weakly. (1)
Reference
1. Musselman CA, Lalonde ME, Cote J, Kutateladze TG.Perceiving the epigenetic landscape through histone readers. Nat Struct Mol Biol.2012;19(12):1218-27. PMID: 23211769.
Chromodomain: The chromodomain is the smallest member, consisting of four curved β-strands and an α-helix. The chromodomains of HP1 and Polycomb were found to recognize histone H3 trimethylated at K9 (H3K9me3) and H3K27me3, respectively, and these proteins were the first examples of readers specific for methyllysine. Chromodomains generally prefer trimethylated lysine, though some have been shown to bind dimethylated species. The aromatic cage of the chromodomain of mouse and fly HP1 contains an aspartate or glutamate residue, accounting for its ability to interact well with H3K9me3 and dimethylated H3K9 (H3K9me2). (1)
Reference
1. Musselman CA, Lalonde ME, Cote J, Kutateladze TG.Perceiving the epigenetic landscape through histone readers. Nat Struct Mol Biol.2012;19(12):1218-27. PMID: 23211769.