Chemical shift assignments for S. cerevisiae Ubc13.

ABSTRACT

The ubiquitination pathway controls several human cellular processes, most notably protein degradation. Ubiquitin, a small signaling protein, is activated by the E1 activating enzyme, transferred to an E2 conjugating enzyme, and then attached to a target substrate through a process that can be facilitated by an E3 ligase enzyme. The enzymatic mechanism of ubiquitin transfer from the E2 conjugating enzyme onto substrate is not clear. The highly conserved HPN motif in E2 catalytic domains is generally thought to help stabilize an oxyanion intermediate formed during ubiquitin transfer. However recent work suggests this motif is instead involved in a structural, non-enzymatic role. As a platform to better understand the E2 catalyzed ubiquitin transfer mechanism, we determined the chemical shift assignments of S. cerevisiae E2 enzyme Ubc13.