New Simple, Economical Bioseparation Technique Using Self-Purifying, Self-Cleaving Affinity Tags

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Princeton Invention # 04-2076



Researchers at Princeton University have developed a new economical method for the purification of recombinant proteins expressed in E. coli. In this method, the host cells simultaneously produce both an affinity tagged product protein and an easily recovered granular affinity carrier. The self-cleaving capability of the affinity tag allows the simple recovery of a native target protein at reasonable yield and very low cost. This simple technique is likely to be portable to numerous other expression hosts and is a significant advance in the large-scale production of recombinant protein products.  This system has been successfully used at laboratory scale to purify several active test proteins at reasonable yield. It is expected that this combination of improved economics and simplicity will constitute a significant breakthrough in both large-scale production of purified proteins and enzymes and high-throughput proteomic studies of peptide libraries.


The method developed within the Chemical Engineering Department of Princeton University, combines two well established technologies to generate a breakthrough in protein production and purification. The first is the production of polyhydroxybutyrate (PHB) granules in engineered strains of E. coli. The second is a recently developed group of self-cleaving affinity tags based on protein splicing elements known as inteins. By combing these technologies with a PHB-binding protein, a self-contained protein expression and purification system has been developed. In this system, the PHB-binding protein effectively acts as an affinity tag for desired product proteins. The tagged product proteins are expressed in an E. coli strain that also produces intracellular PHB granules, where they bind to the granules via the PHB-binding tag. The granules and attached proteins can then be easily recovered following cell lysis by simple mechanical means such as filtration or centrifugation. Once purified, the product protein is self-cleaved from the granules and released into solution in a substantially purified form. By allowing the bacterial cells to effectively produce both the affinity resin and tagged target protein, the cost associated with the purification of recombinant proteins could be greatly reduced.


References :


Gillies, A. R., Hsii, J. F., Oak, S. & Wood, D. W., 2008, Rapid cloning and purification of proteins: Gateway vectors for protein purification by self-cleaving tags (Editors┬┐ Choice feature publication), Biotechnology and Bioengineering, Vol. 101 (2), 229-240.


Mee, C., Banki, M. R. and Wood, D. W., 2008, Towards the Elimination of Chromatography in Protein Purification: Expressing Proteins Engineered to Purify Themselves, Chemical Engineering Journal, Vol. 135, 56-62.


Banki, M.R. & Wood, D.W., 2005, Inteins and Affinity Resin Substitutes for Protein Purification and Scale Up, Microbial Cell Factories, Vol. 4:32.


Barnard, G.C., McCool, J.D., Wood, D.W. & Gerngross T.U., 2005, An Integrated Recombinant Protein Expression and Purification Platform, Applied and Environmental Microbiology, Vol. 71, 5735-5742.


Banki,M., Gerngross,T.,  Wood, D., 2005, Novel and economical purification of recombinant proteins: Intein-mediated protein purification using in vivo polyhydroxybutyrate (PHB) matrix association, Protein Science, Vol. 14, 1387-1395.


Princeton is currently seeking industrial collaborators to commercialize this technology.

For more information on Princeton University Invention # 04-2076 please contact:



                                Laurie Tzodikov

                                Office of Technology Licensing and Intellectual Property

                                Princeton University

                                4 New South Building

                                Princeton, NJ 08544-0036

                                (609) 258-7256

                                (609) 258-1159 fax



Patent Information:
For Information, Contact:
Laurie Tzodikov
Licensing Associates
Princeton University
David Wood
Mahmoud Banki
Tillman Gerngross