Difference between revisions of "Part:BBa K3185001"
(→‎Purification)
Line 32: Line 32:
 
<br>
 
<br>
 
<br>
 
<br>
−
[[File:TmEncapsulin.png|800px|thumb|left|alt text]]
+
[[File:TmEncapsulin.png|300px|thumb|left|alt text]]
 
<br>
 
<br>
 
<br>
 
<br>

Revision as of 02:00, 21 October 2019


Tm Encapsulin

Usage and Biology

TmEncapsulin is a protein found from Thermotoga maritima. A paper says that it consists of 60 monomers and forms capsule, Virus-like particle(VLP)[1]. iGEM also treats it as a useful part (BBa_K192000).

We used TmEncapsulin as biological polymer, because it consists of 60 monomers. This part has three tag sites. First is 6x-His tag placed in the C-terminus of TmEncapsulin for protein purification by using Ni-NTA beads. However, in a paper, Ni-NTA beads cannot bind to 6x-His tag added in C-terminus because it doesn’t display enough to the surface of the protein capsule[2]. To solve this problem, we inserted second tag. Second is HAtag inserted between TmEncapsulin and 6x-His tag in expectation of C-terminus to display on the surface of the capsule. Third is 6x-His-tag and linker inserted between #43 and #44 amino acids of native encapsulin for improving heat-resistance of TmEncapsulin. To design third one, we refered BBa_K2686002 of iGEM EPFL 2018 and the same paper.(BBa_K2686002)

We put it between BamHI site and Ndel site on pET11-a. The expression plasmids were introduced into BL21(DE3) and expressed by T7 promoter/ T7 RNAP system. Ni-NTA agarose was used for the purification.

Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    COMPATIBLE WITH RFC[12]
  • 21
    INCOMPATIBLE WITH RFC[21]
    Illegal BglII site found at 77
    Illegal BglII site found at 492
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    COMPATIBLE WITH RFC[25]
  • 1000
    INCOMPATIBLE WITH RFC[1000]
    Illegal SapI.rc site found at 426
    Illegal SapI.rc site found at 457

Purification


Expression

  • Cells were grown in 200ml LB media (100μg/ml Ampicillin) at 37oC shaking at 140 rpm to an OD600 of 0.5, verifying via a spectrophotometer.
  • Protein was expressed in 0.1mM IPTG for 2hours.

SDS-PAGE



alt text







































Result

Fig. 1 TmEncapsulin polymer appears as the peak.
TmEncapsulin expressed E. coli lysate and purified protein solution was loaded on 10%-60% sucrose linear gradient / 20 mM Tris 7.5, 50 mM NaCl, then centrifuged in 100,000g for 18 hours at 4℃ with SW41(Beckman). The solution was fractionated on a 96-well plate with BioComp. At the same time, 260nm absorption was measured.



Fig. 2 SDS-PAGE of the fraction



Fig. 3 Isopeptide bond formation between Plastic binding proteins and Encapsulin.
3µL of SpyCatcher-Plastic-binding protein (SpyC-PBP) solution and 3µL of SpyTag inserted TmEncapsulin (SpyTmEnc) solution was mixed, then placed for 16h at room temperature. Then 6µL of 2x SDS sample buffer was added. 10µL of each sample was loaded. SDS-PAGE for 30min in 200V. The gel was CBB stained.



References

1 Lukarska, M., Fournier, G., Pflug, A., Resa-Infante, P., Reich, S., Naffakh, N., and Cusack, S. (2017).
Structural basis of an essential interaction between influenza polymerase and Pol II CTD.
Nature 541, 117–121.

2 Moon, H., Lee, J., Min, J., and Kang, S. (2014).
Developing genetically engineered encapsulin protein cage nanoparticles as a targeted delivery nanoplatform.
Biomacromolecules 15, 3794–3801.