Fig. 3

Distinct Uba1 architectures accommodate different E2-binding modes. a Middle, superimposition of Uba1-Cdc34, Uba1-Ubc4 (PDB:4II2), and Uba1-Ubc15 (PDB:5KNL) complexes by the UFD. Cdc34 is colored blue, Ubc4 is green, Ubc15 is gray. hA/UFD interface and catalytic cysteine positioning are highlighted by black boxes. Left, zoomed in, head-on view of E2 hA binding to Uba1 UFD. Right, zoomed in view of catalytic cysteine positions. b Cartoon schematic of difference in angle of hA bound to Uba1 for each E2 pair, as in a. c Left, superimposition of Uba1–E2 complexes by the SCCH with the E2/SCCH interface highlighted by a black box. Right, zoomed in view of the E2/SCCH interface. d Superimposition of Uba1–E2 complexes by the AAD with the E2, UFD, and SCCH shown. Relative differences in rotation for the UFD (left) and SCCH (right) are indicated by arrows