Chemical Synthesis of Ubiquitinated Proteins for Biochemical Studies

Ubiquitination, the attachment of ubiquitin to a target protein via isopeptide linkage, has emerged as a vibrant research topic in chemical biology. Ubiquitination regulates almost all aspects of cell biology including cell signaling, DNA repair, and protein degradation by the 26 proteasomes. To deepen our understanding of the role of ubiquitin system on cell biology and its relevance to health and disease, one must be able to produce highly homogeneous ubiquitinated proteins in adequate amounts. However, the molecular biology and enzymatic methods are very much limited to generate many of these targets. In this context, chemical protein synthesis fortunately brings exciting opportunities to allow to construct desired ubiquitinated proteins with defined length of ubiquitin chains in workable amounts. This book chapter highlights the recent developments from our group on synthesis of different ubiquitin conjugates to address fundamental biological questions relevant to ubiquitin biology.