| nucleosome | <cell biology> Repeating units of organisation of chromatin fibres in chromosomes, consisting of around 200 base pairs and two molecules each of the histones H2A, H2B, H3 and H4. most of the DNA (around 140 base pairs) is believed to be wound around a core formed by the histones, the remainder joins adjacent nucleosomes, thus forming a structure reminiscent of a string of beads. Origin: Gr. Soma = body (18 Nov 1997) |
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| nucleosomes | The repeating structural units of chromatin, each consisting of approximately 200 base pairs of DNA wound around a protein core. This core is composed of the histones h2a, h2b, h3, and h4. (12 Dec 1998) |