Part:BBa_K3815033
HIV-1 reverse transcriptase p51
Description of this part
Targeted protein
This part is used to purify homemade Reverse Transcriptase. This is derived from HIV-1(Human Immunodeficiency Virus). This enzyme is more thermotolerant than normal reverse transcriptase, making it useful for LAMP(Loop-Mediated Isothermal Amplification)) and RT-LAMP(Reverse Transcription Loop-Mediated Isothermal Amplification). A peptide made from one ORF is partially digested in an infected cell and becomes two fragments, p66 and p51. It is known that the HIV-1 RT functions when the p66 and p51 form a heterodimer. To purify them as recombinant proteins in E.coli, we separately expressed and purified p66 and p51, and dimerized them in vitro before use. This part is to express p51. We examined our homemade reverse transcriptase activity in vitro. We used total yeast DNA/RNA for this assay. We selected the intron-containing region of Rpl19A as a template for reverse transcription. If there is no reverse transcription, the genomic DNA including an intron is amplified by PCR, resulting in a band of 876 bp. On the other hand, if cDNA is correctly synthesized by reverse transcription, a band of 370 bp without an intron should appear. As shown below, the cDNA band was successfully observed in an RT-dependent manner. From this result, we concluded the activity of homemade RT.
Sequence and Features
- 10INCOMPATIBLE WITH RFC[10]Illegal PstI site found at 320
- 12INCOMPATIBLE WITH RFC[12]Illegal PstI site found at 320
- 21COMPATIBLE WITH RFC[21]
- 23INCOMPATIBLE WITH RFC[23]Illegal PstI site found at 320
- 25INCOMPATIBLE WITH RFC[25]Illegal PstI site found at 320
Illegal AgeI site found at 966 - 1000COMPATIBLE WITH RFC[1000]
Purification
Expression
- Cells were cultivated in 1000ml LB media at 37oC shaking at 180 rpm to the log-phase.
- when the OD600 reaches 0.35-0.7, IPTG was added at the final concentration of 0.5mM to induce the peptide expression.
- After 3 hours of induction, cells were harvested and frozen in liquid-N2.
- We added purified p66(BBa_K3815034) and p51(BBa_K3815033) to the same tube and incubated them at -30oC for 4 days to make a dimer.
Purification
After the cell disruption by sonication, each protein was purified using Ni-NTA beads. Samples were eluted by a four-step gradient of Imidazole.(70mM, 95mM, 120mM, 270mM)
Fig2 shows the result of SDS-PAGE.
Lane 5,6,7,8 are the result of Reverse Transcriptase.
We observed the correct bands in the SDS-PAGE gel. The arrowheads indicate the targeted proteins.
Reference
Kellner, M.J., Ross, J.J., Schnabl, J., Dekens, M.P.S., Heinen, R., Grishkovskaya, I., Bauer, B., Stadlmann, J., Menéndez-Arias, L., Fritsche-Polanz, R., et al. (2020). A rapid, highly sensitive and open-access SARS-CoV-2 detection assay for laboratory and home testing.
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