Histone H1

Histone H1(s)

Histone H2a

Histone H2b

Histone H3

Histone H3.3

Histone H4

Histone H5

Histone H7

Small chromosomal proteins (approx 12-20 kD) possessing an open, unfolded structure and attached to the DNA in cell nuclei by ionic linkages. Classification into the various types (designated histone I, histone II, etc.) is based on the relative amounts of arginine and lysine in each.