title: Nucleosome arrays reveal the two-start organization of the chromatin fiber.
abstract: Chromatin folding determines the accessibility of DNA constituting eukaryotic genomes and consequently is profoundly important in the mechanisms of nuclear processes such as gene regulation. Nucleosome arrays compact to form a 30-nanometer chromatin fiber of hitherto disputed structure. Two competing classes of models have been proposed in which nucleosomes are either arranged linearly in a one-start higher order helix or zigzag back and forth in a two-start helix. We analyzed compacted nucleosome arrays stabilized by introduction of disulfide cross-links and show that the chromatin fiber comprises two stacks of nucleosomes in accord with the two-start model.
authors.affiliation: Eidgenössische Technische Hochschule (ETH) Zürich, Institute for Molecular Biology and Biophysics, ETH-Hönggerberg, CH-8093 Zürich, Switzerland.
authors.forename: Benedetta
authors.initials: B
authors.lastname: Dorigo
authors.forename: Thomas
authors.initials: T
authors.lastname: Schalch
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kulangara
authors.forename: Sylwia
authors.initials: S
authors.lastname: Duda
authors.forename: Rasmus R
authors.initials: RR
authors.lastname: Schroeder
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Richmond
mesh_terms: D000818:Animals; D002843:Chromatin / Q000737:chemistry* / Q000648:ultrastructure; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006657:Histones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008854:Microscopy, Electron; D008954:Models, Biological; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry; D009154:Mutation; D009707:Nucleosomes / Q000737:chemistry* / Q000648:ultrastructure; D017510:Protein Folding; D014982:Xenopus laevis
chemical_list: D002843:Chromatin; D006657:Histones; D046912:Multiprotein Complexes; D009707:Nucleosomes; D004247:DNA