title: Replacement of histone H3 with CENP-A directs global nucleosome array condensation and loosening of nucleosome superhelical termini.
abstract: Centromere protein A (CENP-A) is a histone H3 variant that marks centromere location on the chromosome. To study the subunit structure and folding of human CENP-A-containing chromatin, we generated a set of nucleosomal arrays with canonical core histones and another set with CENP-A substituted for H3. At the level of quaternary structure and assembly, we find that CENP-A arrays are composed of octameric nucleosomes that assemble in a stepwise mechanism, recapitulating conventional array assembly with canonical histones. At intermediate structural resolution, we find that CENP-A-containing arrays are globally condensed relative to arrays with the canonical histones. At high structural resolution, using hydrogen-deuterium exchange coupled to mass spectrometry (H/DX-MS), we find that the DNA superhelical termini within each nucleosome are loosely connected to CENP-A, and we identify the key amino acid substitution that is largely responsible for this behavior. Also the C terminus of histone H2A undergoes rapid hydrogen exchange relative to canonical arrays and does so in a manner that is independent of nucleosomal array folding. These findings have implications for understanding CENP-A-containing nucleosome structure and higher-order chromatin folding at the centromere.
authors.affiliation: Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Tanya
authors.initials: T
authors.lastname: Panchenko
authors.forename: Troy C
authors.initials: TC
authors.lastname: Sorensen
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Woodcock
authors.forename: Zhong-Yuan
authors.initials: ZY
authors.lastname: Kan
authors.forename: Stacey
authors.initials: S
authors.lastname: Wood
authors.forename: Michael G
authors.initials: MG
authors.lastname: Resch
authors.forename: Karolin
authors.initials: K
authors.lastname: Luger
authors.forename: S Walter
authors.initials: SW
authors.lastname: Englander
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Hansen
authors.forename: Ben E
authors.initials: BE
authors.lastname: Black
mesh_terms: D001324:Autoantigens / Q000235:genetics*; D002503:Centromere / Q000235:genetics*; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics*; D004278:DNA, Superhelical / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D057890:Epigenomics; D006657:Histones / Q000737:chemistry / Q000235:genetics; D006801:Humans; D013058:Mass Spectrometry; D046529:Microscopy, Electron, Transmission; D009690:Nucleic Acid Conformation; D009707:Nucleosomes / Q000235:genetics* / Q000648:ultrastructure; D011487:Protein Conformation; D014461:Ultracentrifugation
chemical_list: D001324:Autoantigens; C000619700:CENPA protein, human; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone; D004278:DNA, Superhelical; D006657:Histones; D009707:Nucleosomes