title: Acetylation of histone H3 at the nucleosome dyad alters DNA-histone binding.
abstract: Histone post-translational modifications are essential for regulating and facilitating biological processes such as RNA transcription and DNA repair. Fifteen modifications are located in the DNA-histone dyad interface and include the acetylation of H3-K115 (H3-K115Ac) and H3-K122 (H3-K122Ac), but the functional consequences of these modifications are unknown. We have prepared semisynthetic histone H3 acetylated at Lys-115 and/or Lys-122 by expressed protein ligation and incorporated them into single nucleosomes. Competitive reconstitution analysis demonstrated that the acetylation of H3-K115 and H3-K122 reduces the free energy of histone octamer binding. Restriction enzyme kinetic analysis suggests that these histone modifications do not alter DNA accessibility near the sites of modification. However, acetylation of H3-K122 increases the rate of thermal repositioning. Remarkably, Lys --> Gln substitution mutations, which are used to mimic Lys acetylation, do not fully duplicate the effects of the H3-K115Ac or H3-K122Ac modifications. Our results are consistent with the conclusion that acetylation in the dyad interface reduces DNA-histone interaction(s), which may facilitate nucleosome repositioning and/or assembly/disassembly.
authors.affiliation: Department of Biochemistry, Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Mridula
authors.initials: M
authors.lastname: Manohar
authors.forename: Alex M
authors.initials: AM
authors.lastname: Mooney
authors.forename: Justin A
authors.initials: JA
authors.lastname: North
authors.forename: Robin J
authors.initials: RJ
authors.lastname: Nakkula
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Picking
authors.forename: Annick
authors.initials: A
authors.lastname: Edon
authors.forename: Richard
authors.initials: R
authors.lastname: Fishel
authors.forename: Michael G
authors.initials: MG
authors.lastname: Poirier
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Ottesen
mesh_terms: D000107:Acetylation; D000818:Animals; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D006657:Histones / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism*; D009707:Nucleosomes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D029867:Xenopus Proteins / Q000737:chemistry / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D004268:DNA-Binding Proteins; D006657:Histones; D009707:Nucleosomes; D029867:Xenopus Proteins; D004247:DNA