Part:BBa_K2244011

CloE promoter+TorA+opdA+T1 terminator

The device is a functional composite part containing a coding sequence opdA (BBa_K215090) with a TorA signal peptide fused to its N-terminus for protein export (BBa_K2244003).

Biology

-Co1E promoter (BBa_K2244006) is derived from the promoter region of colicin E gene located in the ColE1 plasmid of E.coli. ColE promoter contains a ‘SOS’ operator region that allows the binding of LexA protein to repress transcription. DNA-binding component of LexA repressor in LEV1 would form a dimer and bind to the operator sequence thus halts the activity of ColE promoter.

- TorA-opdA(BBa_K2244003) contains a signal peptide fused to the N-terminus of opdA. opdA encodes organophosphate hydrolase (OPH) which is a homodimeric organophosphate triesterase that requires metal ion as a cofactor to degrade a wide range of toxic organophosphates. OPH can hydrolyze various phosphorus-ester bonds including P-O, P-F, P-CN, and P-S bonds. TorA is an E. coli twin-arginine signal peptide bearing a consensus motif of SRRxFLK. TorA-opdA allows exportation of opdA encoding protein to periplasmic space.

-T1 terminator (BBa_B0010), it is the most used terminator in E. coli system.

Usage

In our project this year, this device worked in the lightOFF system (BBa_k2244009) to replace the ColE promoter+mCherry+T1 terminator section and to allow the expression of periplasmic OPH when induced in darkness. To demonstrated the functionality of this part, we performed ELISA studies, enzymatic activity and whole cell stability studies (Figure 1-3) to prove that functional OPH was successfully secreted in periplasmic.

Figure 1: ELISA studies of OPH protein expression in periplasmic fraction, cytoplasmic fraction, whole cell, and periplasmic fraction of pLEV1(408) (control strain).

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Figure 2: Specific OPH activities of whole cell, periplasmic fraction, cytoplasmic fraction and control periplasmic fraction (lightOFF). The activity was assayed with paraoxon as substrate. Data are mean values+/-standard derivations from three replicates.

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Figure 3: illustration of OPH activity vs various concentrations of periplasmic fractions from OPH-expressed cell strain (black) and control strain (Red). The activity was assayed with paraoxon as substrate. Data are mean values+/-standard derivations from three replicates.

Reference

1) Bulina, M. E., Chudakov, D. M., Britanova, O. V. & Lukyanov. K.. 2003. A genetically encoded photosensitizer. Nat. Biotechnol. 24, 95-99.

2)Tour, O., Meijer, R. M., Zacharias, D. A., Adams, S. R. & Tsien, R. Y, 2003. Genetically targeted chromophore-assisted light inactivation. Nat. Biotechnol. 21, 1505–1508.

3)Wong, E. V., David, S., Jacob, M. H. & Jay, D. G, 2003. Inactivation of myelin-associated glycoprotein enhances optic nerve regeneration. J. Neurosci. 23, 3112–3117.

4)Takemoto, K., Matsuda, T., Sakai, N., Fu, D., Noda, M., Uchiyama, S., Kotera, I., Arai, Y., Horiuchi, M., Fukui, K. and Ayabe, T., 2013. SuperNova, a monomeric photosensitizing fluorescent protein for chromophore-assisted light inactivation. Scientific reports.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  INCOMPATIBLE WITH RFC[21]

  Illegal XhoI site found at 1286
  
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 383
  Illegal AgeI site found at 578
  Illegal AgeI site found at 917
  
• 1000
  COMPATIBLE WITH RFC[1000]