Figure 2.

Fold and Structure of M48^USP-UbVME

(A) Ribbon representation of the M48^USP structure (gray with the β hairpin in orange) in complex with UbVME (green). The secondary structure elements are labeled, and the side chains of catalytic triad residues are shown in yellow.

(B) Electrostatic surface potential representation of M48^USP with bound Ub shown in a ribbon representation (top). Below, Ub, in an electrostatic surface potential representation, was rotated 180° to show the charge distribution on the face forming the interface. Note the charge complementarity between the M48^USP acidic cleft and the positively charged Ub C terminus.

(C) The final 2F_o − F_c electron density map contoured at 1.3 σ indicates a covalent bond between the catalytic C23 and the Cβ atom of the former vinylmethylester moiety at the Ub C terminus.