Office of Technology Transfer – University of Michigan

Protein Solubilizing Fusion Partners

Technology #3734


Owing to its low cost and compatibility with automation and scale up, E. Coli remains the most widely used host for the high-through production of proteins. While the use of E. Coli as a host often results in formation of insoluble aggregates, this is commonly addressed through the use of fusion tags to enhance solubility. In this regard, maltose-binding protein (MBP) appears to be one of the most effective in solubilizing passenger proteins during expression. However, MBP fusion proteins may precipitate during purification, and incomplete removal of MBP from the protein may lead to interference with subsequent applications of the protein.


Researchers at the University of Michigan have developed a new protein fusion partner to address some of the current limitations associated with the solubilization and purification of proteins. The novel fusion protein tag has solubilizing activity, and is smaller than MBP, and thus interferes less with downstream applications such as nuclear magnetic resonance or crystallization. The new fusion tag is compatible with high throughput cloning and expression processes. Moreover, the tag may also function as affinity tag for use in purification of the passenger protein, and is less likely to require removal from the purified fusion protein.

Applications and Advantages


  • Solubilization and purification of proteins, including high throughput applications


  • Enhanced solubility as compared to MBP
  • Small and compact structure, and may not need to be removed from the fusion protein for subsequent applications