title: Structural characterization of macroH2A containing chromatin.
abstract: MacroH2A (mH2A) is one of the most recently identified members of the heteromorphous histone variant family. It is unique among the members of this group because it contains an unusually large non-histone C-terminal end, from where its name derives, and appears to be restricted to subphylum vertebrata. Although a concerted effort has been carried out in order to characterize the physiological relevance of mH2A, little is known in comparison about the structural importance of the molecule. Elucidating the biophysical and conformational proprieties of mH2A in chromatin may provide clues into the links between this histone variant and its unique function(s). In this paper, we look first at the heterogeneous tissue-specific distribution of this protein in different vertebrate classes. This is followed by a structural comparison between mH2A and H2A protein and by the characterization of the nucleosome core particles with which these histone subtypes are associated. We find that the highly alpha-helical C-terminus of mH2A confers an asymmetric conformation to nucleosomes and that this variant is tightly bound to chromatin fragments in a way that does not depend on the overall extent of acetylation of the other core histones.
authors.affiliation: Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada, V8W 3P6.
authors.forename: D Wade
authors.initials: DW
authors.lastname: Abbott
authors.forename: Mario
authors.initials: M
authors.lastname: Laszczak
authors.forename: John D
authors.initials: JD
authors.lastname: Lewis
authors.forename: Harvey
authors.initials: H
authors.lastname: Su
authors.forename: Susan C
authors.initials: SC
authors.lastname: Moore
authors.forename: Melissa
authors.initials: M
authors.lastname: Hills
authors.forename: Stefan
authors.initials: S
authors.lastname: Dimitrov
authors.forename: Juan
authors.initials: J
authors.lastname: Ausió
mesh_terms: D000107:Acetylation; D000818:Animals; D002645:Chickens; D002843:Chromatin / Q000737:chemistry*; D004912:Erythrocytes / Q000737:chemistry; D006367:HeLa Cells; D006657:Histones / Q000737:chemistry*; D006801:Humans; D007059:Ictaluridae; D008099:Liver / Q000737:chemistry; D008297:Male; D009707:Nucleosomes / Q000737:chemistry; D009928:Organ Specificity; D010446:Peptide Fragments / Q000737:chemistry; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011892:Rana catesbeiana; D013737:Testis / Q000737:chemistry; D014461:Ultracentrifugation
chemical_list: D002843:Chromatin; D006657:Histones; D009707:Nucleosomes; D010446:Peptide Fragments; C120756:macroH2A histone