Figure 3. Conformations of the β1β2 loop.

A) Final multiconformer model of the β1β2 loop for the core mutant. Backbone atoms in the loop are rendered in sticks, while the side chains are left as lines.

B) Final model of β1β2 loop for the affinity matured mutant. Panel shown with electron density in Supplementary Figure 2.

C) Backbone conformational ensemble from NMR relaxation dispersion experiments (PDB ID: 2k39). The majority of conformations exhibit a simple backbone shift, producing a hinge like motion as observed in previous MD simulations.

D) β1β2 loop conformations from different ubiquitin structures. Wild-type ubiquitin apo-structure (PDB ID: 1ubq) in grey, and bound to USP7 in orange (PDB ID: 1nbf). The core mutant is shown in dark blue, and the affinity matured in green.

See also Figure S2.