ABSTRACT

The firm association of histones with DNA in chromatin leaves little doubt that this is the natural existence of these two macromolecular species. Since the binding of histones and DNA is primarily electrostatic, it is difficult to understand why histones do not associate in similar complexes with RNA or nonhistone proteins. In addition to the extensive associations with each other that result in the formation of macromolecular aggregates, histones or protamines can interact with a considerable number of other proteins. Since the nonhistone proteins, although present in lesser amounts than histones, are an essential part of chromatin, there is a distinct possibility that both the nonhistone proteins and histones interact to a various extent. The various interactions of histones with certain chromatin nonhistone proteins were found to be selective in that the nature of the complexes depended on the individual nonhistone and histone protein fractions.