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A
Cartoon representation of the 1.5 Å Wolbachia pipientis wMelOTU crystal structure with labeled termini, missing regions, and features of the active site.
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B
Structural alignment of the core OTU folds (central β‐sheet and two supporting α‐helices) from human OTUB1 (green, PDB 4DDG) and wMelOTU (purple). Surrounding regions are less well conserved and shown as semi‐transparent.
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C
Enlarged region of the OTUB1:Ub structure (PDB 4DDG) showing entry of the Ub C‐terminus (red) into the OTUB1 active site (green). The wMelOTU structure (purple) is overlaid to highlight the structural conflict between the downward position of the His‐loop and the Ub C‐terminus.
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D
1.8 Å crystal structure of the covalent wMelOTU‐Ub complex. wMelOTU (cartoon, pink) is linked to the Ub (surface, red) C‐terminus through its active site. Primary, secondary, and tertiary regions of the Ub‐binding S1 site are indicated.
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E
Structural overlay of the apo (violet) and Ub‐bound (pink) wMelOTU structures highlighting the repositioning of the His‐loop to accommodate entry of the Ub C‐terminus, as well as ordering of two regions in the S1 site that form an embrace around Ub.
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F
Detailed view of the primary and secondary interfaces between wMelOTU (pink) and Ub (red) observed in the wMelOTU‐Ub structure. wMelOTU and Ub residues participating in the interface are shown with ball and stick representation.
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G
Ub‐KG(TAMRA) cleavage assay monitoring the effects of structure‐guided wMelOTU mutations. These data were collected in parallel with those presented in Fig
1G, and the WT dataset is shown again for reference.
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H
Detailed view of the wMelOTU (pink) active site region and its coordination of the Ub C‐terminus (red). Residues that coordinate Ub or stabilize the active site are shown with ball and stick representation.
