THE THERMAL-DENATURATION OF HISTONES (H2A, H3, H2B) IN THE PRESENCE OF SURFACTANTS

The thermal denaturation of the histones H-2A and H-3, and their sodiu m n-dodecyl sulphate (SDS) complexes was studied spectroscopically ove r the range 30-90-degrees-C at pH 6.4. The Pace theoretical model was used to determine the free energy and heat capacity of the denaturatio ns. The effect of SDS on the stabilization of the histones H-2A and H- 3 was estimated from their thermodynamic parameters as well as from th eir melting temperatures, which indicated a compact structure for the histone-SDS complexes. In contrast, these values are inconsistent for the effect of dodecyl trimethyl ammonium bromide (DTAB), suggesting th at DTAB induces the unfolding of the histones, H-2A, H-3, and H2B.