Fig. 2. OtDUB_1–259–ubiquitin crystal complex reveals three distinct ubiquitin-binding sites.

a Overall structure of the OtDUB_1–259–ubiquitin complex with OtDUB_1–259 in cartoon representation and individual ubiquitin molecules in cartoon/surface representation. Catalytic triad residues shown as sticks in a, b. b Schematic of the potential K63 ubiquitin-chain linkage, highlighting the arrangement of two neighboring ubiquitin molecules bound to OtDUB_1–259. K63 side chains shown as sticks and C-terminal glycines shown as red spheres. c Structural comparison of OtDUB_1–259–S1 ubiquitin complex with other bacterial DUB–ubiquitin complexes. For XopD–Ub (orange, PDB ID: 5JP3) and SdeA–Ub (green, PDB ID: 5CRB), DUBs are shown as cartoon, S1 ubiquitin is shown as cartoon/surface, and Ile44 is shown as magenta sticks.