title: Structure of HP1 chromodomain bound to a lysine 9-methylated histone H3 tail.
abstract: The chromodomain of the HP1 family of proteins recognizes histone tails with specifically methylated lysines. Here, we present structural, energetic, and mutational analyses of the complex between the Drosophila HP1 chromodomain and the histone H3 tail with a methyllysine at residue 9, a modification associated with epigenetic silencing. The histone tail inserts as a beta strand, completing the beta-sandwich architecture of the chromodomain. The methylammonium group is caged by three aromatic side chains, whereas adjacent residues form discerning contacts with one face of the chromodomain. Comparison of dimethyl- and trimethyllysine-containing complexes suggests a role for cation-pi and van der Waals interactions, with trimethylation slightly improving the binding affinity.
authors.affiliation: Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA 22908-0733, USA.
authors.forename: Steven A
authors.initials: SA
authors.lastname: Jacobs
authors.forename: Sepideh
authors.initials: S
authors.lastname: Khorasanizadeh
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D029721:Drosophila Proteins / Q000737:chemistry / Q000378:metabolism; D006657:Histones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006860:Hydrogen Bonding; D008239:Lysine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism*; D008745:Methylation; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D017354:Point Mutation; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D029721:Drosophila Proteins; D006657:Histones; D010455:Peptides; C452193:heterochromatin protein 1, Drosophila; D000090266:Chromobox Protein Homolog 5; C003712:trimethyllysine; D008239:Lysine