Fig. 2: Structure of KLHDC3-EloB/C bound to a C-terminal Gly degron.
From: Structural basis for C-degron selectivity across KLHDCX family E3 ubiquitin ligases
a Overall structure of UB bound to KLHDC3-EloB/C. UB (orange), KLHDC3 (light blue), EloC (cyan), and EloB (pale cyan) are shown in surface representation. b Cartoon representation of UB (orange) bound to KLHDC3 (light blue). UB’s C-terminal Gly76 (orange) is shown in sticks. Blades 1–6 of the KLHDC3 propeller are labeled. The barrel beta-strands for one blade are labeled A-D. c Cartoon representation of the “funnel-like” arrangement of KLHDC3’s substrate binding pocket. UB (orange) is shown in cartoon with its C-terminal Gly76 shown in spheres. KLHDC3 (light blue) is shown in cartoon with transparent surface. d Bottom (left) and top (right) views of KLHDC3 (light blue; surface). UB (orange,cartoon) is shown with its C-terminal Gly76 in sticks. The relative dimensions of the C-degron binding pocket and the C and N chambers of the KLHDC3 are labeled. e Electrostatic representation of KLHDC3 bound to UB (orange) with its C-terminal Gly76 in sticks. Hydrophobic surfaces are colored white, positively charged surfaces blue, and negatively charged surfaces red. f LigPlot of interactions between UB and KLHDC3, hydrogen bonds between KLHDC3 and UB or water (red, spheres) are show in black dashes. g Close up view of KLHDC3’s (light blue) C-degron binding pocket. Residues from UB (orange) and KLHDC3 forming interactions are shown in sticks with black dashes between interacting partners. h Quantification of pulse-chase ubiquitylation assays monitoring UBE2R2 mediated ubiquitylation of UB or the indicated UB mutants by WT monomericc CRL2KLHDC3 or the indicated KLHDC3 mutants. i Structural view of interactions between the globular domain of UB (orange) and KLHDC3 (light blue). Probable interacting residues are shown in sticks. j Quantification of pulse-chase ubiquitylation assays monitoring UBE2R2 mediated ubiquitylation of WT UB or UB globular domain mutants by monomeric CRL2KLHDC3. Bar graphs are the average of n = 2 independent experiments. Source data are provided as a Source Data file.
