sv40 chromatin can be isolated in two forms : at moderate ionic strength ( mu = 0.1-0.3 ) it contains histone h1 in addition to the four nucleosomal histones and has a highly condensed appearance in the electron microscope , being composed of a few closely connected large spheres [ 190 a ( 160 , 220 ) diameter ] .
C0028623
nucleosomal
C0019652
histones