Figure 2. Comparisons of Gs-DCN1L with EF-hand containing proteins and Sc-DCN1, and modeling of the Cul1-Rbx1-DCN1L complex.

(A) The N-terminal EF-hand pair of Gs-Dcn1L (black) was superposed with the following EF-hand pair containing proteins: troponin C (green), caltractin (red) and Cdc31p (blue) and rendered as ribbons in this stereodiagram. Helix 5 of Gs-Dcn1L and the binding partners of the other EF-hand pairs, Troponin I, Kar1 and Sfi1p, respectively, were not included in the superposition. (B) Gs-DCN1L (slate) and Sc-DCN1 (gray) were superposed and rendered as cartoons in this stereodiagram. Using the Gs-DCN1L naming convention, Helices 8–10 were labeled as H8-H10. Residues lining the hydrophobic pocket formed by Helices 8–10 are displayed as sticks. Except for Ile244 of Sc-DCN1, all labeled residues correspond to the Gs-DCN1L model. The major anchor point of the Gs-DCN1L 9–10 loop, Tyr172, is included. A line was drawn between Asp168 of Gs-DCN1L and Ile244 of Sc-DCN1 to indicate the positional disparity of these sequence related residues, and the gross differences in polypeptide chain morphology between the two respective DCN1Ls. Note that the 9–10 helix of Gs-DCN1L was not fully modeled due to its high mobility. (C) Gs-DCN1L (colored as in Figure 1B) was modeled onto the Cul1-Rbx1 complex (gray and black, respectively), and shown as a stereodiagram. This was accomplished by superposition of Gs-DCN1L onto the Sc-DCN1/Cdc53 complex (PDB 3O2P), and through superposition of Cdc53 upon Cul1 of the SCF ubiquitin ligase complex (PDB 1LDK). Atoms of the NEDD8 reactive Cul1 residue, Lys720, are shown as spheres.