Chromatography of different forms of DNA on immobilized histone columns

Histones 1, 2A, 2B, 3, 4, and 5 from chicken erythrocytes have each been covalently immobilized on agarose beads and tested for their ability to bind DNA. Both calf thymus DNA and PM-2 viral DNA (form II, a nicked circle) bind to columns of immobilized histone at low ionic strength and can be eluted with 0.2--0.8 M NaC1, depending on the histone column. The strength of DNA binding by histone columns is in the order H5 greater than H1 greater than greater than H2B approximately H3 greater than H4 approximately H2A. About 70% of a heat-denatured calf thymus DNA sample and 100% of a supercoiled (form I) PM-2 DNA sample bind very tightly to histone columns and are released only by strong protein denaturants.