6r94
From Proteopedia
Cryo-EM structure of NCP_THF2(-3)
Structural highlights
Function[H2B1J_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.[1] [2] [3] 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.[4] [5] [6] Publication Abstract from PubMedAccess to DNA packaged in nucleosomes is critical for gene regulation, DNA replication and DNA repair. In humans, the UV-damaged DNA-binding protein (UV-DDB) complex detects UV-light-induced pyrimidine dimers throughout the genome; however, it remains unknown how these lesions are recognized in chromatin, in which nucleosomes restrict access to DNA. Here we report cryo-electron microscopy structures of UV-DDB bound to nucleosomes bearing a 6-4 pyrimidine-pyrimidone dimer or a DNA-damage mimic in various positions. We find that UV-DDB binds UV-damaged nucleosomes at lesions located in the solvent-facing minor groove without affecting the overall nucleosome architecture. In the case of buried lesions that face the histone core, UV-DDB changes the predominant translational register of the nucleosome and selectively binds the lesion in an accessible, exposed position. Our findings explain how UV-DDB detects occluded lesions in strongly positioned nucleosomes, and identify slide-assisted site exposure as a mechanism by which high-affinity DNA-binding proteins can access otherwise occluded sites in nucleosomal DNA. DNA damage detection in nucleosomes involves DNA register shifting.,Matsumoto S, Cavadini S, Bunker RD, Grand RS, Potenza A, Rabl J, Yamamoto J, Schenk AD, Schubeler D, Iwai S, Sugasawa K, Kurumizaka H, Thoma NH Nature. 2019 May 29. pii: 10.1038/s41586-019-1259-3. doi:, 10.1038/s41586-019-1259-3. PMID:31142837[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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