Figure 17.

Structural dissection of the X. laevis nucleosome core particle (PDB ID: 1AOI). (A) Complete nucleosome core particle wrapped in DNA (double white-pink ribbon). (B) The nucleosome core particle after the DNA removal. (C1 and C2) H2A–H2B dimers. (C1a) and (C1b) represent histones H2A (gray) and H2B (orange) of the first H2A–H2B dimer, whereas (C2a) and (C2b) show histones H2A (silver) and H2B (green) of the second H2A–H2B dimer. (D) (H3–H4)₂ tetramer. (D1 and D2) H3–H4 dimers. (D1a) and (D1b) represent histones H3 (blue) and H4 (red) of the first H3–H4 dimer, whereas (D2a) and (D2b) show histones H3 (yellow) and H4 (tan) of the second H3–H4 dimer. All of these structures were visualized using the VMD software.⁵⁰⁹