X‐Ray Studies of Nucleoproteins Depleted of Lysine‐Rich Histone

It appears that the lysine-rich histones are not essential for the formation of the supercoiled structure and upon their removal the depleted nucleoprotein forms a more regular structure.

Abstract

A method is described for the clean and quantitative removal of lysine‐rich histones from chicken‐erythrocyte and calf‐thymus nucleoproteins. X‐ray diffraction studies have been made of the whole nucleoproteins and those depleted of lysine‐rich histones. The whole nucleoproteins show the series of low‐angle rings characteristic of the native form of nucleohistone which have been attributed by Wilkins (1964) to a supercoiled structure. Removal of the lysine‐rich histones from the calf‐thymus and chicken‐erythrocyte nucleoproteins results in a sharpening of the low‐angle X‐ray rings. It appears that the lysine‐rich histones are not essential for the formation of the supercoiled structure and upon their removal the depleted nucleoprotein forms a more regular structure.