title: hSWI/SNF-catalyzed nucleosome sliding does not occur solely via a twist-diffusion mechanism.
abstract: Nucleosome remodeling by the hSWI/SNF complex and other chromatin remodeling complexes can cause translocation (sliding) of the histone octamer in cis along DNA. Structural and biochemical evidence suggest that sliding involves a DNA twist-diffusion process whereby the DNA rotates about the helical axis without major displacement from the surface of the nucleosome and that this process may be driven by torsional stress within the DNA. We report that hSWI/SNF efficiently catalyzes sliding of nucleosomes containing branched DNAs as steric blocks to twist-diffusion and a nick to allow dissipation of torsional stress within the nucleosome. These results suggest that SWI/SNF-catalyzed nucleosome sliding does not occur exclusively via a simple twist-diffusion mechanism and support models in which the DNA maintains its rotational orientation to and is at least partially separated from the histone surface during nucleosome translocation.
authors.affiliation: Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642, USA.
authors.forename: Sayura
authors.initials: S
authors.lastname: Aoyagi
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Hayes
mesh_terms: D000818:Animals; D001692:Biological Transport; D002384:Catalysis; D002843:Chromatin / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004265:DNA Helicases; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism; D004058:Diffusion; D006657:Histones / Q000378:metabolism; D006801:Humans; D017665:Hydroxyl Radical; D008957:Models, Genetic; D009687:Nuclear Proteins; D009690:Nucleic Acid Conformation; D009707:Nucleosomes / Q000502:physiology*; D011485:Protein Binding; D021381:Protein Transport; D011994:Recombinant Proteins / Q000378:metabolism; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D014981:Xenopus
chemical_list: D002843:Chromatin; D004268:DNA-Binding Proteins; D006657:Histones; D009687:Nuclear Proteins; D009707:Nucleosomes; D011994:Recombinant Proteins; C499336:SMARCA1 protein, human; C084011:SMARCA2 protein, human; D014157:Transcription Factors; D017665:Hydroxyl Radical; D004247:DNA; D004262:DNA Restriction Enzymes; D003850:Deoxyribonuclease I; C084108:SMARCA4 protein, human; D004265:DNA Helicases