Figure 1.

Modifications of the nucleosome face. Histone post-translational modifications located on the nucleosome face may influence chromatin structure through multiple mechanisms. (A) These modifications might regulate chromatin–protein interactions in either a positive (top) or negative (bottom) fashion. (B) Alternatively, these modifications could affect higher order chromatin structure by altering interactions between neighboring nucleosomes. (C) Surface modifications are modeled on the crystal structure of the nucleosome (pdb file 1AOI) (10). The histone proteins are shown in a ribbon diagram with histone H2A shown in red, H2B in orange, H3 in blue and H4 in green. The DNA helix is shown in gray. Modified residues are depicted as spheres and colored yellow. Image was generated using the program Pymol.