δ-mercaptolysine assisted ubiquitination

The field of chemical biology of ubiquitin is gaining significant interest in recent years due to the diversity and complexity of the ubiquitin signal in numerous biological functions in eukaryotes. The inability of biological methods to prepare ubiquitinated peptides and proteins with full control over the ubiquitination sites, types, and lengths of the ubiquitin chains is one of the main challenges in the ongoing efforts to fully understand the ubiquitin signal at the molecular level. This has been a major driving force for the development of chemical tools to complement biological methods in preparing ubiquitin bioconjugates for various biochemical and structural studies. This review deals with the recent advances in developing chemical methods for the synthesis of ubiquitinated peptides and proteins assisted by δ-mercaptolysine, which enable isopeptide formation in a highly efficient and chemoselective manner.