[Is the binding strength of histone fractions with DNA different?]

The dissociation of histones H1, H2B and H2A from DNA was shown for the first time in the medium of physiological ionic strength (0.15M NaCl + 0.7 mM Na-phosphate buffer, pH 7.0) by treating the whole histone--DNA complex with high concentrations of whole histone from calf thymus chromatin. The histones can be separated into three groups according to the strength of their binding to DNA: H1 < H2B + H2A < H3 + H4. It is suggested that histone octamer is not a conservative formation and the histone content of nucleosomes may change under physiological conditions being affected by competition of chromatin components for DNA.