Understanding E2 Mechanism using NMR

Abstract

The ubiquitination pathway controls human cellular processes such as cell cycle division, DNA transcription and repair, and immune responses. In these processes, ubiquitin is covalently attached to a substrate protein by the combined efforts of an E1 activating enzyme, an E2 conjugating enzyme, and an E3 ubiquitin ligase. We are concerned with investigating the catalytic mechanism of ubiquitin transfer onto the substrate protein. We specifically want to understand how the structure of Ubc13 helps with catalytic activity. The structure of yeast Ubc13, an E2 conjugating enzyme, has been solved using nuclear magnetic resonance (NMR). The study of the structure of Ubc13 compared to that of Ubc13 bound to ubiquitin in the active site will show the changes in the active site upon binding. Through the use of transition state mimics of ubiquitin conjugating reaction we will completely describe how Ubc13 stabilizes the ubiquitination conjugation pathway.