Fig. 3.
Crystal structure of ZUFSP232-578 in covalent complex with Ub-PA. a Overview of the crystal structure in cartoon representation. The catalytic core of ZUFSP is shown in gray, ubiquitin in blue. The MIU region on helix α1 of ZUFSP is colored green, the zUBD region in cyan. The putative S1’ ubiquitin-binding α2/α3 helices are shown in red. The catalytic triad is shown as sticks and colored orange. b Structural superposition of the catalytic domain of ZUFSP (blue) and UFSP2 (3OQC, cyan) in two perspectives. RMS distance is 3.65 Å over 200 residues. c Magnification of the active site of ZUFSP (gray). The catalytic triad is colored orange, putative components of the oxyanion hole in green and Trp-423, closing the substrate binding groove directly next to the active site, is in dark pink. Ubiquitin is shown in blue color. The active sites of Ufsp2 (cyan) and papain (violet) are superimposed. Structurally equivalent residues of Ufsp2 and ZUFSP are shown as sticks. Important residues of ZUFSP (black), Ufsp2 (cyan) and papain (violet) are labeled. Important ubiquitin residue labels contain asterisks. In the available structure (3OQC) of UFSP2, the catalytic cysteine was mutated to a serine, indicated here as ‘S294