Recombinant protein expression in insect cells varies greatly from protein to protein. A
fusion tag that is not only a tool for detection and purification, but also enhances expression
and/or solubility would greatly facilitate both structure/function studies and therapeutic
protein production. We have shown that fusion of SUMO (small ubiquitin-related modifier) to
several test proteins leads to enhanced expression levels in Escherichia coli. In eukaryotic
expression systems, however, the SUMO tag could be cleaved by endogenous de …