s. Classes Histones "are highly conserved and can be grouped into five major classes: H1/H5, H2A, H2B, H3, and H4". These are organised into two super-classes as follows: core histones – H2A, H2B, H3 and H4 linker histones – H1 and H5 Two of each of the core histones assemble to form one octameric nucleosome core particle by wrapping 146 base pairs of DNA around the protein spool in 1.65 left-handed super-helical turn. The linker histone H1 binds the nucleosome and the entry and e… (More on Histones)