A) Nucleosomes were assembled with yeast histones and 181 bp DNA fragments with variants of the sea urchin 5S rDNA NPS in which the native DraI site was moved from position 78 to the sites indicated (). The NPS identified in animal histones () is shown in the grey bar, and the observed location of yeast histone cores on these DNA fragments is shown in blue. B) Results of a typical DraI digestion with a 181 bp DraI-78 nucleosome with or without yFACT. C) DraI digestion rates were calculated for nucleosomes alone, with Nhp6 added, or with yFACT added (Nhp6 and Spt16-Pob3). Averages and standard deviations from at least three measurements with each variant template are shown (). Results for DraI-152, DraI-157, and free DNA are given above the chart and in or . D) As in panel A, except templates with a recognition site for PstI are shown with the observed position of histone cores in green. E) The approximate locations of the recognition sites for DraI and PstI are mapped onto the structure of the yeast nucleosome () assuming alignment of the left ends of the linear DNAs in each case. DNA regions contacted by H2A–H2B are colored red, and those contacted by H3–H4 are colored blue. An intact nucleosome is shown on the left, with just the DNA shown for the variant template sets. Red (DraI) or green (PstI) spheres indicate the phosphodiester linkage digested. F) As in panel C, except the rates of PstI digestion are shown for the templates in panel D.