An Electrophoretic Comparison of Vertebrate Histones

Abstract We have studied histones from a wide range of vertebrates with high resolution electrophoresis. There are five major electrophoretic fractions of histone in all somatic tissues in all species examined. Two fractions of histone have a constant electrophoretic mobility no matter what their source. Two fractions vary somewhat from class to class of vertebrate; and one fraction, the lysine-rich fraction, varies considerably in mobility, indicating substantial changes in its primary structure during evolution. This interpretation is confirmed by separation of the individual histone fractions and amino acid analysis. Electrophoretic heterogeneity is found within several of these fractions in good agreement with previous reports on calf histones (Panyim and Chalkley, Biochemistry 8, 3972 (1969)). The electrophoretic heterogeneity within Fractions F2al and F3 is manifested by bands which, while varying in relative intensity from species to species, nonetheless always have a constant mobility. On the other hand the extent of the electrophoretic heterogeneity of the lysine-rich histone group varies among species indicative of a much less stringent demand for a constancy of primary sequence of these molecules relative to the more arginine-rich histone molecules.