Part:BBa_K4241018
Mxe_GyrA_Intein with PT linker and ELK16
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21INCOMPATIBLE WITH RFC[21]Illegal XhoI site found at 676
- 23COMPATIBLE WITH RFC[23]
- 25INCOMPATIBLE WITH RFC[25]Illegal NgoMIV site found at 499
Illegal NgoMIV site found at 514 - 1000COMPATIBLE WITH RFC[1000]
Overview
This is part is to be fused to a target protein of interest for inclusion expression. This part also features the ability for DTT mediated cleavage for downstream purification purposes. It is noted that this is a mutant version.
This is derived from the following publication: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6173929/
Usage and Biology
ELK16 is the basis of a self-assembling peptide-fused protein expression system, SA-ELK16 system. ELK16 indues the formation of active fusion protein aggregates in E. coli, these aggregates are easiily and cheaply purified by centrifugation. The protein of interest can then be seperated by cleaving intein via DTT mediated cleavage. The summation of this allows for high purity, cost-effective purification scheme
Purification scheme:
1. Express fusion protein and sonicate cells
2. Centrifuge and remove supernatent. The fusion protein aggregates will form and fall to the bottom.
3. Treat with DTT to cleave the protein of interest from the aggregates
4. Centrifuge and remove supernatent. The pure, protein will be solubized whereas the uncleaved protein and insoluble aggregates will remain at the bottom.
Results
After sonication, the protein is released from the cells. In cells expressing intein-ELK16, the RFP-tagged fusion protein remains in an aggregated and insoluble fraction.
Fig. 1. Left: Sonicated bacteria RFP-Intein-ELK16 system. Right: Sonicated bacteria 6xHis-SUMO-RFP.
Fig. 2. SDS PAGE results depicting cleaved RFP after overnight DTT cleavage of RFP-intein fusion.
The RFP was precipitated in 2.5% acetic acid to release the RFP from the intein fusion. It was then resolubized in with urea and high salt solution. The ELK16 remains in the insoluble fraction.
Fig. 3. RFP is denatured with acetic acid (as shown by the loss of color), but could be refolded in 8M Urea to regain RFP red colour rapidly to be back to natural folding.
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