Fig. 3. Interfaces of Uba1/Cdc34^A141K–Ub(t)^OPEN structure.

a Top, Uba1/Cdc34^A141K-Ub(t)^OPEN structure with surfaces of Uba1 domains and Cdc34 gray with only contacting residues colored. Ub(t) is represented as loop and colored limon. Bottom, Network of contacts between Uba1, Cdc34, and Ub(t) with involved residues shown as sticks with red oxygen atoms, blue nitrogen atoms, and yellow sulfur atoms. Hydrogen bonds are indicated by dashed lines. b Surface representations of Uba1, Cdc34, and Ub(t) shown in open book representation with residues in the interface colored hot pink (FCCH domain), light magenta (SCCH domain), cyan (E2), and limon (Ub(t)). c E1–E2 thioester transfer assays of the indicated mutants for Uba1 FCCH and SCCH domains. Data are represented by mean ± SD with three independent technical replicates labeled above and individual replicates shown as black circles. Gel images are representative of independent technical replicates (n = 3). Source data are provided as a Source Data file. d Sequence alignment of Uba1s FCCH and SCCH across different species with Uba1’s secondary structure cartoon shown above sequence. Shaded boxes indicate Uba1 residues that interact with the Ub(t).