Difference between revisions of "Part:BBa K3699009"

Revision as of 00:36, 28 October 2020

mlrA gene with 6xHis tag

Parts for purification of mlrA--BBa_K3699009 & BBa_K3699010

In Contribution, we replaced the original promoter J23110 with the stronger constitutive promoter J23119, and new data from experiments were added to the existing part BBa_K1378001.

In order to explore the properties of purified mlrA enzyme, we designed BBa_K3699009 & BBa_K3699010.

Usage and Biology

Design

We used the T7 promoter plus 6 x His tag and MBP tag to improve the efficacy and efficiency of expression and purification. Sequences encoding fusion proteins 6xHis-mlrA (BBa_K3699009) and 6xHis-MBP-mlrA (BBa_K3699010) are improved parts of BBa_K1378001.

Maltose Binding Protein (MBP) is a member of the maltose/maltodextrin system of E.coli， which is accountable for the uptake and efficient catabolism of maltodextrins. MBP elevates the yield of its fusion partner in many cases and is often able to promote the solubility of polypeptides to which it is fused.

S-tag sequences are novel fusion peptide tags for recombinant proteins that allow detection by rapid, sensitive homogeneous assays or by colorimetric detection in Western blotting. S-tag can be used to purify target protein

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Figure 1. Skeleton map of pET-mlrA and pET-MBP-mlrA. We added 6xHis tag and s-tag at both ends of the gene, and linked MBP with mlrA (BBa_K1378001). MBP is a solubilization tag, which can increase the solubility of protein in water. S-tag can be used to purify target protein.

Construction

1. Replicating the mlrA DNA through PCR, Gel Electrophoresis and Extraction of MlrA

2. The pET-DuetI and mlrA genes were digested by BamHI-XhoI double enzyme to construct the plasmid pET-mlrA.

3. Transforming the plasmid to E. coli JM109 to express the targeted protein.

4. Purifying the protein MlrA and utilizing HPLC to determine the effectiveness of the protein MlrA.

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Figure 2. Plasmid Profile. pET-mlrA.

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Figure 3. Plasmid Profile.<b> MBP tag and mlrA gene are inserted into pET-MBP-mlrA.</p>

Testing

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           We tried to verify whether the two plasmids were successfully constructed. It demonstrated the success of
           plasmid construction.</p>
       
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Figure 5. SDS page of JM109 harboring plasmid pET-mlrA. Inclusion bodies are formed.

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Figure 6. Results of PCR and DNA gel electrophoresis. Left: PCR; Right: DNA gel electrophoresis (4222 bp, 3096 bp)

Result

The 6xHis-mlrA of pET skeleton was introduced into E.coli BL21 (DE3), and the protein containing the tagged target gene was also expressed. Although, the purification of the protein is still in process due to limited time.

Sequence and Features