FIGURE 10.

The interaction surfaces between UB^K48R and Ube2g1^C90S mapped on a model of the oxyester complex. A, intramolecular UB^K48R-interaction surfaces on Ube2g1^C90S are highlighted on the structure of free Ube2g1. The red and yellow colors, respectively, indicate high and low magnitude CSPs. The residues in which the HSQC peaks shifted too much to be traced are shown in green (see Fig. 9C). B, Ube2g1^C90S-interacting surface of UB^K48R is highlighted using magenta, red, orange, and yellow colors to indicate high to low magnitude of CSPs, respectively. The residues colored black represent prolines and other residues that were invisible in the HSQC spectrum, and the green-colored residues indicate where resonances disappeared in the oxyester complex. C, the residues of UB^K48R showing different chemical shifts between the oxyesters with Ube2g1^C90S and Ube2g1^{C90S/Y102G/Y104G} are highlighted as in panel B. D, the residues of Ube2g1 mutated for the ubiquitylation assays (Fig. 12) are shown superimposed onto a ribbon representation of the structure. E, surface presentation shows the donor UB^K48R-occupied surface of the E2.