Fig. 5.

The nucleosome promotes active, closed E3-E2~Ub conformations. a Superposition of E3-E2~Ub structures in the open state with E3 RNF165 and the E2-E3-nucleosome model for RNF168 indicates that nucleosome surface clashes with such open states. b Superposition of RING E3-E2~Ub structures and the E2-E3-nucleosome model for RNF168 shows that the model is compatible with the closed state of the E3-E2~Ub complex. There are no direct interactions between the nucleosome surface and Ub. Target lysine, here labeled as K15, catalytic center, and gateway loop are indicated. Color coding indicated in the Figure