Chromatins are highly ordered nuclear structures that contain DNA, histones, and other chromosomal proteins. The fundamental unit of chromatin is the nucleosome, which is wrapped by 147 base pairs of genomic DNAs. The nucleosome consists of two copies of the four core histones (H): H2A, H2B, H3, and H4, which are tied together by the linker histone H1. Each histone within the nucleosome contains a flexible N-terminus tail
Common Design 