Part:BBa_K3185010

SPYCatcher -> engineered PETase

Usage and Biology

Engineered PETase is a protein from Ideonella sakaiensis. The paper tries to improve the binding activity and the degradation activity of PET [1].

We used engineered PETase which shows a higher binding affinity to PET than PETase in order to compare them. We put SpyCatcher(BBa_K1159200) on N-terminus of PETase because we used SpyCatcher/SpyTag system to bind it to other parts. It has three tags and a cleavage site. First is 6×His-tag inserted in the N-terminus of SpyCather for protein purification. Second is MYC-tag inserted between SpyCatcher and PETase to detect it by using the antibody. Third is a TEV protease site because, in the paper, it was used for protein purification [2]. However, we didn’t use it in our experiment.

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
  INCOMPATIBLE WITH RFC[12]

  Illegal NheI site found at 751
  
• 21
  INCOMPATIBLE WITH RFC[21]

  Illegal XhoI site found at 1318
  
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal AgeI site found at 1074
  
• 1000
  COMPATIBLE WITH RFC[1000]

Purification

Fig.1

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.

Purification

1. E.coli which expressed this part were lysed with sonification.
2. Proteins are purified from lysate with Ni-NTA agarose(QIAGEN).
3. Imidazole eluates were visualized and confirmed by SDS-PAGE followed by CBB staining.

This purification method failed. As shown in Fig.1, we didn't see any band in the specific molecular weight of the protein.

References

1 Austin, H.P., Allen, M.D., Donohoe, B.S., Rorrer, N.A., Kearns, F.L., Silveira, R.L., Pollard, B.C., Dominick, G., Duman, R., Omari, K. El, et al. (2018).
Characterization and engineering of a plastic-degrading aromatic polyesterase.
Proc. Natl. Acad. Sci. U. S. A. 115, E4350–E4357.

2 Veggiani, G., Nakamura, T., Brenner, M.D., Gayet, R. V., Yan, J., Robinson, C. V., and Howarth, M. (2016).
Programmable polyproteams built using twin peptide superglues.
Proc. Natl. Acad. Sci. U. S. A. 113, 1202–1207.