Supplementary Figure 3: Structural characterization of dinucleosome binding by the full PRC2–AEBP2 complex
From: Cryo-EM structures of PRC2 simultaneously engaged with two functionally distinct nucleosomes
(a) Visualization of the movement of nucleosomes in the group 2 of PRC2 dinucleosome complexes (Fig. 1c). Marked in red, the nucleosome proximal to the CXC and SET domains of EZH2 on the top lobe, moves by about 40 Å across the different configurations observed. Marked in green, the nucleosome proximal to the bottom lobe of PRC2, moves very dramatically with respect to the complex and its structure is poorly defined in most of the class averages, pointing to both translation and rotation and thus, a very flexible tethering. (b) Further quantitation of the variability in position of the nucleosome distal from the active site within group 2 of PRC2 dinucleosome complexes (Fig. 1c). The nucleosome near the N-terminal part of SUZ12 moves up to >130 Å, whereas the potential substrate nucleosome near the active site of EZH2 is less flexible. Left, compilation of all classes in group 2 with red arrows marking the distance from the RBAP48 WD40 domain to the nucleosome as well as the angle. Middle panel, same arrows as in the left panel, without the 2D class averages for clearer visualization. Right, all arrows indicating all observed positions of this nucleosome, superimposed with their origin at the RBAP48 WD40 domain. The range of possible distances and orientations becomes clear. The average distance from RBAP48 to the nucleosome (shortest distance) is 83 Å ± 20 Å.
