SUMO Fusion Technology for Enhanced Protein Production in Prokaryotic and Eukaryotic Expression Systems

In eukaryotic cells, the reversible attachment of small ubiquitin-like modifi er (SUMO) protein is a post-translational modifi cation that has been demonstrated to play an important role in various cellular processes. Moreover, it has been found that SUMO as an N-terminal fusion partner enhances functional protein production in prokaryotic and eukaryotic expression systems, based upon significantly improved protein stability and solubility. Following the expression and purification of the fusion protein, the SUMO-tag can be cleaved by specific (SUMO) proteases via their endopeptidase activity in vitro to generate the desired N-terminus of the released protein partner. In addition to its physiological relevance in eukaryotes, SUMO can, thus, be used as a powerful biotechnological tool for protein expression in prokaryotic and eukaryotic cell systems.In this chapter, we will describe the construction of a fusion protein with the SUMO-tag, its expression in
Escherichia coli
, and its purification followed by the removal of the SUMO-tag by a SUMO-specific protease in vitro.