The conformation of the histone octamer complex in solution has been shown, by circular dichroism studies, to be highly dependent on the nature of the salt milieu and its concentration. In 2 M NaCl, the complex has 43.5% alpha-helix, 16% beta-sheet, and 40.5% random structure. In 2.3 M (NH4)2SO4, the octamer has 49.0% alpha-helix and 51% random structure. These results partially explain the discrepant results obtained by the X-ray analysis of crystals obtained under varying conditions.