Histones H2A, H2B, H3 and H4 are known as the core histones which means that there are building nuclesome. H1 is known as the linker histone which binds to the "linker DNA" region between nucleosomes, helping stabilize the chromatin fiber. The linker histone H1 binds the nucleosome at the entry and exit sites of the DNA, thus locking the DNA into place and allowing the formation of higher order structure.
