5oy7
Structure of the 4_601_157 tetranucleosome (P1 form)Structure of the 4_601_157 tetranucleosome (P1 form)
Structural highlights
FunctionH2B11_XENLA 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. Publication Abstract from PubMedChromatin fiber organization is implicated in processes such as transcription, DNA repair and chromosome segregation, but how nucleosomes interact to form higher order structure remains poorly understood. We solved two crystal structures of tetranucleosomes with approximately 11 base pair DNA linker length at 5.8 and 6.7A resolution. Minimal intramolecular nucleosome-nucleosome interactions result in a fiber model resembling a flat ribbon that is compatible with a two-start helical architecture, and that exposes histone and DNA surfaces to the environment. The differences in the two structures combined with electron microscopy reveal heterogeneous structural states, and we used site-specific chemical crosslinking to assess the diversity of nucleosome-nucleosome interactions through identification of structure-sensitive crosslink sites that provide a means to characterize fibers in solution. The chromatin fiber architectures observed here provide a basis for understanding heterogeneous chromatin higher order structures as they occur in a genomic context. Capturing structural heterogeneity in chromatin fibers.,Ekundayo B, Richmond TJ, Schalch T J Mol Biol. 2017 Sep 9. pii: S0022-2836(17)30424-2. doi:, 10.1016/j.jmb.2017.09.002. PMID:28893533[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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