H3 H4 Research Articles

Histone-histone interactions. I. An electrophoretic study.

Whole histone extracted from chromatin by either acid or protamine displacement was found by gel electrophoresis at pH7 to contain only two histone complexes, H2A-H2B and H3-H4, and uncomplexed histone H1. Although both complexes are dissociated at low pH or with high urea concentrations, removal of the denaturant resulted in complete complex reformation within minutes at the most. A syntematic investigation of binary, ternary and quaternary histone mixtures revealed that interactions also occur between histones H2B-H4 and H2A-H4. No evidence however was found for the formation of ternary and quaternary histone complexes.

On the native structure of the histone H3–H4 complex

Electrophoretic and sedimentation velocity studies on the histone H3–H4 complex show that provided the H3 cysteine residues remain reduced the complex reforms quantitatively when removed from a variety of denaturing conditions. If histone H3 is allowed to become intramolecularly oxidized while denatured only monomer and large aggregates are formed on return to native conditions. At pH 7 ionic strength 0.1 the complex remains with reduced sulfhydryl groups indefinitely suggesting a vital role for the sequence 96–110 in histone H3 in the tertiary structure of the complex.