Fig. 2: 3D Organization of nucleosomes in native chromatin fibres.

a Two distinct classes of native nucleosomes. Class 1 (top) (82% of the total population, n = 5578) is fitted with the nucleosome crystal structure PDB 7DBP, with H1 density coloured in magenta. Class 2 (bottom) (18% of the total population, n = 1212) is fitted with the core nucleosome crystal structure PDB 6ESF. b Mapping back of individual nucleosomes from Class 1 (left) and Class 2 (right) into the representative tomogram according to their coordinates and orientations. c A rotated tomographic slice (Y axis: -16°, from Fig. 1d) depicting two clear chromatin fibres (dashed outlines). Scale bar = 50 nm. d Mapping back of individual nucleosomes in chromatin fibres in c. The H1 density is coloured magenta, indicating the side of entry and exit of the linker DNA, from which the DNA path (dashed lines) is predicted. Three representative sub-regions (circled) are enlarged on the right panel.