Part:BBa_K3185001

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. Also, this has three tag sites. First is 6×His-tag inserted in the C-terminus of TmEncapsulin for protein purification. Second is HA-tag inserted between TmEncapsulin and 6x-His tag to detect it by using the antibody. Third is a 6x-His tag inserted between the C-terminus of Encapsulin and 6x-His tag because, in a paper, it is said that 6x-His tag inserted in the C-terminus of Encapsulin is not presented on the surface of Encapsulin well, so it can’t bind to Ni-NTA Agarose beads .In the same paper, it is also said that heat-resistance is improved when inserting 6x-His tag and linker between #43 and #44 amino acids of native encapsulin, so we designed like that[2].

We put it between BamHI site and Ndel site on pET11-a. We used BL21 (DE3) for gene expression. We used Ni-NTA Agarose beads for purification. After that, we confirmed molecular weight of TmEncapsulin by using SDS-PAGE.

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 37^oC 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. 10 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.

Fig. 9 SDS-PAGE of the fraction

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.