Figure 2.

The three-dimensional structure of a nucleosome combined with a schematic representation of post-translational modifications (PTMs) on the histone tails assembled from recent articles [31,36,37,38,39,40,41,42,43,44,45,46]. The nucleosome structure was rendered in top view by PyMol [47] using PDB structure 1kx5 [48]. Histone proteins are shown in cartoon representation as wrapped by the DNA double helix. The N- and C-terminal tails of histone proteins pass through the cylinder of the supercoiled DNA and are available for reader proteins recognizing the PTMs, key components of the histone code system.