Team:UC Berkeley/ProteinPurification


Revision as of 08:57, 20 October 2008 by Aronlau (Talk | contribs)


Protein purification involves a series of step to isolate the protein of interest. Purifying a protein from E.coli first includes an extraction step, which brings the protein into solution. There are many physical or chemical methods from which to select for extraction. However, many times the potein of interest may be too fragile such that putting the protein through harsh extractions will permanently damage the protein, resulting in low yield. The proposed solution for this is to transform an inducible λ phage lysis device. This gives one complete control over lysis rate. In addition, using a natural form of lysis is much gentler on the cells and proteins, which will lead to greater success of protein extraction and purifcation.

Additional steps can be taken to lower the background that comes from genomic DNA and RNA that flow into solution from extraction. Engineering the ability to make the restriction enzymes BamHI and BgIII and ribonuclease barnase will greatly reduce background.


Proof of Concept Experiment

To prove the protein purification concept, a plasmid coding for a protein with a His tag is transformed into E.coli with the arabinose induced self-lysis device. This culture will be induced to lyse with arabinose, releasing the His-tagged protein. The cellular debris is pelleted by centrifuging for 30 seconds. The supernatant will be added to a new tube and Ni-NTA will be added to it. The supernatant and Ni-NTA solution is incubated at 4 degree Celcius for 4 hours. The Ni-NTA protein complex is concentrated using a magnet. The protein is eluted from Ni-NTA and the solution is ran on a gel to see whether or not protein is purified.