Crystal structure of the SOCS2-elongin C-elongin B complex defines a prototypical SOCS box ubiquitin ligase -- Bullock et al. 103 (20): 7637 Data Supplement - HTML Page - index.htslp -- Proceedings of the National Academy of Sciences

Bullock et al. 10.1073/pnas.0601638103.

Supporting Figures

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Supporting Figure 5
Supporting Figure 6
Supporting Figure 7

Fig. 5. Elongin B stabilizes the SOCS2-elongin C complex structure by 20°C. Unfolding was monitored by using a fluorescent temperature shift assay and SpyroOrange as a probe. The presence of elongin B leads to a significant thermal stabilization of the complex. In its absence, the SOCS2-elongin C dimer shows unfolding at physiological temperature.

Supporting Figure 6

Fig. 6. Model for the assembly of SOCS2-elongin C-elongin B into an E3 ubiquitin ligase complex with Cul-5, Rbx2, and an E2 ubiquitin-conjugating enzyme. Homology models for Cul-5 and Rbx2 were built in ICM (Molsoft, San Diego) by using the Skp2-Skp1-Cul-1-Rbx1 structure (PDB ID code 1LDK). The structural homology between Skp1 and elongin C was used to locate SOCS2-elongin C-elongin B. Similarly, the E2 subunit was superimposed from the c-Cbl-UbcH7 structure (PDB ID code 1FBV) by using the homology between Rbx1 and c-Cbl.

Supporting Figure 7

Fig. 7. Potential drug pocket in the SOCS2-elongin C interface. SOCS2 is shown in a surface representation colored by electrostatic potential. A pocket of 340 Å³ formed between elongin C loop 5 (yellow) and SOCS2 H1 is indicated by blue wire-frame. A water molecule is shown at the back of the pocket bound through two hydrogen bonds to the side chain of Y157 and the C-terminal carboxyl group (SOCS box). The entrance to the pocket is lined by the SOCS box H1 residue K173.