Studies on histone oligomers. I. Reconstitution and fractionation of homotypic histone oligomers.

Abstract

Histone oligomers were reconstituted from calf thymus whole histones by annealing from 2 M NaCl-5 M urea-0.05 M Tris buffer (pH 8.0)-1% beta-mercaptoethanol, and were fractionated in terms of solubility in ammonium sulfate solution. Fractionation occurred according to the histone compositions of oligomers. The oligomers thus obtained were (1) pentamer and trimer of H1, (2) tetramer of H2A and H2B, and (3) tetramer and higher aggregates of H3 and H4, under the following ionic conditions: 0.5 M NaCl-0.05 M phosphate buffer (pH 7.0). The aggregates of H3 and H4 could easily be converted to the tetramer by lowering of pH.