The ZnF-UBP domain of Sad1 binds one Zn atom. (A) Sad1's ZnF-UBP domain (pale orange) with secondary structure elements labeled, including loop L2A and the β4-5 loop. This view is from a 50° rotation about the y-axis of the full-length molecule in Figure 3B with the iUSP domain removed for clarity. (B) A structural alignment produced with Pymol of Sad1's ZnF-UBP to the ZnF-UBP domain from H. sapiens USP16 (yellow; PDB ID 2I50). The three zinc atoms of USP16, A through C, appear as gray spheres, and the B-site zinc atom from Sad1 appears as a pale orange sphere. (C) Structural alignment of the B-site zincs from SAD1 ZnF-UBP, H. sapiens HDAC6 ZnF-UBP (violet, PDB ID 3C5K), and USP16 ZnF-UBP. The residues that comprise the CCHH zinc finger of Sad1 are labeled.
