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. Author manuscript; available in PMC: 2015 Jul 1.
Published in final edited form as: Nat Chem Biol. 2014 Dec 1;11(1):83–89. doi: 10.1038/nchembio.1700

Figure 4.

Figure 4

NMR ensemble of Ube2w reveals a novel E2 architecture. (a) Solution ensemble of Ube2w derived from NMR restraints (backbone chemical shifts, CSPs, residual dipolar couplings (RDCs), paramagnetic spin-label data, and small-angle X-ray scattering (SAXS)) calculated with CS-Rosetta. The twenty lowest energy members of the ensemble are shown and reveal a well-defined core with high structural similarity to canonical E2s. The C-terminal region is partially disordered and occupies multiple positions near the Ube2w active site C91 (orange). (b) Similar views of a representative canonical UBC domain structure (UbcH5c; PDB 2FUH). (c) Helix-4 (penultimate helix) is in distinct positions in Ube2w (3 representatives of the 20-member ensemble are shown for clarity). A flexible loop emanating from helix-3 leads away from the protein core. Helix-4 is clustered in three distinct positions in the ensemble (Cluster 1, light gray; Cluster 2, gray; Cluster 3, dark gray). (d) Side-view of the full Ube2w ensemble looking down the helix-3 axis reveals the three clusters. (e) In all twenty members of the Ube2w ensemble residues N136-W145 occupy positions beneath the active site, C91 (orange). Residues 119-135 are not shown for clarity. No clustering is evident for this region and the Cβ atom of every residue is on average 14.5-17.5 Å away from the active site.