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Nucleosome - Wikipedia

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A nucleosome is the basic structural unit of DNA packaging in eukaryotes. The structure of a nucleosome consists of a segment of DNA wound around eight histone proteins[1] and resembles thread wrapped around a spool. The nucleosome is the fundamental subunit of chromatin. Each nucleosome is composed of a little less than two turns of DNA wrapped around a set of eight proteins called histones, which are known as a histone octamer. Each histone octamer is composed of two copies each of the histone proteins H2A, H2B, H3, and H4. DNA must be compacted into nucleosomes to fit within the cell nucleus.[2] In addition to nucleosome wrapping, eukaryotic chromatin is further compacted by being folded into a series of more complex structures, eventually forming a chromosome. Each human cell contains about 30 million nucleosomes.[3] Nucleosomes are thought to carry epigenetically inherited information in the form of covalent modifications of their core histones. Nucleosome positions in the genome

Nucleosome Molecular surface model of a Xenopus nucleosome (PDB: 1AOI). Overview SynonymsNucleosome core particle SubunitsDNA, H2A, H2B, H3, H4 Molecular mass~184.5 kDa ClassDNA binding protein FunctionsGenomic compaction Chromatin organization Biological context Organism(s)Eukaryotes LocationNucleus PathwaysChromatin signaling DNA unwinding pathway ProcessesHistone modifications Chromatin accessibility Transcription Repression Identifiers & Data PDB structures6HKT, 1ZBB, 1AOI EMDB IDEMD-26339 EMD-64742 A nucleosome is the basic structural unit of DNA packaging in…

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