Fig. 6. Comparison of the ubiquitin binding site (blue residues) on Tsg101 UEV (yellow) with models for the two distinct ubiquitin binding sites (purple) on the Ubc13/Mms2 heterodimer (gray) (VanDemark et al., 2001). To create the figure, Tsg101 UEV was superimposed on either the Ubc13 E2 (A) or the Mms2 UEV (B) subunits of the Ubc13/Mms2 heterodimer. The figure illustrates the fact that the Ub binding surface on Tsg101 is distinct from previously characterized Ub binding sites on either E2 or UEV domains, but does roughly correspond to the Mms2 binding site on Ubc13.