7pf5
From Proteopedia
Nucleosome 2 of the 4x187 nucleosome array containing H1
Structural highlights
Function[H2B1K_HUMAN] Core component of nucleosome. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling. Has broad antibacterial activity. May contribute to the formation of the functional antimicrobial barrier of the colonic epithelium, and to the bactericidal activity of amniotic fluid. Publication Abstract from PubMedThroughout the genome, nucleosomes often form regular arrays that differ in nucleosome repeat length (NRL), occupancy of linker histone H1 and transcriptional activity. Here, we report cryo-EM structures of human H1-containing tetranucleosome arrays with four physiologically relevant NRLs. The structures show a zig-zag arrangement of nucleosomes, with nucleosomes 1 and 3 forming a stack. H1 binding to stacked nucleosomes depends on the NRL, whereas H1 always binds to the non-stacked nucleosomes 2 and 4. Short NRLs lead to altered trajectories of linker DNA, and these altered trajectories sterically impair H1 binding to the stacked nucleosomes in our structures. As the NRL increases, linker DNA trajectories relax, enabling H1 contacts and binding. Our results provide an explanation for why arrays with short NRLs are depleted of H1 and suited for transcription, whereas arrays with long NRLs show full H1 occupancy and can form transcriptionally silent heterochromatin regions. Histone H1 binding to nucleosome arrays depends on linker DNA length and trajectory.,Dombrowski M, Engeholm M, Dienemann C, Dodonova S, Cramer P Nat Struct Mol Biol. 2022 May;29(5):493-501. doi: 10.1038/s41594-022-00768-w., Epub 2022 May 17. PMID:35581345[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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