Strategies for the expression of SUMO-modified target proteins in Escherichia coli.

We previously described the establishment of a binary vector system that allows co-expression of SUMO conjugation enzymes and a target protein of interest, leading to efficient SUMO modification and the production of a large amount of recombinant SUMO-modified proteins in Escherichia coli. The advantages of this E. coli expression/modification approach include scalability of experiments, low cost, fast growth, and a lack of proteases that cleave the isopeptide linkage between SUMO and the target protein. Thus, this E. coli method provides a useful alternative to authentic SUMO modification assays, such as in vitro SUMO conjugation and in vivo SUMO modification using baculovirus or mammalian cell culture, that are usually complicated, time-consuming and expensive.