title: Single-Molecule Studies of the Linker Histone H1 Binding to DNA and the Nucleosome.
abstract: Linker histone H1 regulates chromatin structure and gene expression. Investigating the dynamics and stoichiometry of binding of H1 to DNA and the nucleosome is crucial to elucidating its functions. Because of the abundant positive charges and the strong self-affinity of H1, quantitative in vitro studies of its binding to DNA and the nucleosome have generated results that vary widely and, therefore, should be interpreted in a system specific manner. We sought to overcome this limitation by developing a specially passivated microscope slide surface to monitor binding of H1 to DNA and the nucleosome at a single-molecule level. According to our measurements, the stoichiometry of binding of H1 to DNA and the nucleosome is very heterogeneous with a wide distribution whose averages are in reasonable agreement with previously published values. Our study also revealed that H1 does not dissociate from DNA or the nucleosome on a time scale of tens of minutes. We found that histone chaperone Nap1 readily dissociates H1 from DNA and superstoichiometrically bound H1 from the nucleosome, supporting a hypothesis whereby histone chaperones contribute to the regulation of the H1 profile in chromatin.
authors.affiliation: Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Hongjun
authors.initials: H
authors.lastname: Yue
authors.affiliation: Department of Biochemistry and Biophysics, Rochester University Medical Center , Rochester, New York 14625, United States.
authors.forename: He
authors.initials: H
authors.lastname: Fang
authors.affiliation: Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Sijie
authors.initials: S
authors.lastname: Wei
authors.affiliation: Department of Biochemistry and Biophysics, Rochester University Medical Center , Rochester, New York 14625, United States.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Hayes
authors.affiliation: Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Tae-Hee
authors.initials: TH
authors.lastname: Lee
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001667:Binding, Competitive; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D006657:Histones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D055767:Immobilized Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008081:Liposomes; D008958:Models, Molecular; D009154:Mutation; D009690:Nucleic Acid Conformation; D056490:Nucleosome Assembly Protein 1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D009707:Nucleosomes / Q000737:chemistry* / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D055503:Protein Multimerization; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D029867:Xenopus Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D006657:Histones; D055767:Immobilized Proteins; D008051:Lipid Bilayers; D008081:Liposomes; C514591:NAP1L1 protein, Xenopus; D056490:Nucleosome Assembly Protein 1; D009707:Nucleosomes; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D029867:Xenopus Proteins; D004247:DNA