Fig. 1.

Structures and interactions of the CSN–CRL2~N8 complex. a The molecular model of CSN–CRL2~N8 fitted into cryo-EM density (8.2 Å resolution) from front and back views. b Conformational clamping of CRL2~N8 by CSN2 and CSN4. Cross-links shown are between CSN4-RBX1 (CSN4^K200-RBX1^K105, purple-green spheres), and four between CSN2–CUL2 (CSN2^K157-CUL2^K489, CSN2^K263–CUL2^K462, CSN2^K225–CUL2^K462, CSN2^K64–CUL2^K404, beige-blue spheres). c View showing ~30 Å separation of CSN6 Ins-2 loop from CSN4 following CRL2~N8 binding. d Modelled position of WHB~N8 using cross-links of the CSN–CRL2~N8. Large scale conformational changes (e) between CSN2 and CSN4 in all apo-CSN crystal structures (PDB 4WSN, 4D10 and 4D18) and CSN–CRL2~N8 (f) CSN5/CSN6 (PDB 4D10) upon binding of CRL2~N8 (holo). Subunits of the CSN–CRL2~N8 were compared with the apo-CSN crystal structure (PDB 4D10) following structural alignment. The structure of the CRL2~N8 has been hidden for clarity