FIGURE 4.

Inter-array self-association is disrupted by the loss of increasing number of histone H4 tails and is affected by their position within an array. A, the effect of number of octamers without H4 tails in a tetranucleosomal array on inter-array self-association is shown. A representative differential centrifugation plot of tetranucleosomal arrays containing zero, one, two, three, or four tailless octamers is shown. The fraction of tetranucleosomal array remaining in the supernatant is plotted as a function of MgCl₂ concentration. B, shown is a histogram representation of the concentration of Mg²⁺ required for 50% sedimentation for tetranucleosomal arrays depicted in A.