Part:BBa_K1017101

Pred ( PompC + B0032 + LacI + J61048 + Plac)

In general, the red light sensing promoter, OmpC promoter, turns on in the dark and turns off under red light with the present of Cph8.

Figure 1.The light receptor cph8 is composed of cph1(pink) and envZ-ompR(maroon).

But we want to construct a more intuitive light regulating th system at can turn on under red light and turn off in the dark. So we created a new biobrick named red promoter by adding a lac operon to inverse the function of OmpC promoter.

Pred, including PompC,RBS(B0032), LacI, ter(J61048), and Plac, can be activated when exposed to red light. OmpR, the transcription factor of PompC, is active when being phosphorylated in dark and inactive under red light. In the presence of red light, the non phosphorylated OmpR cannot turn on PompC. Thus, Plac won't be repressed by the negative regulator, LacI. So the whole Pred can express genes downstream Plac. On the other hand, if there is no red light, the phosphorylated OmpR then turn on PompC, causing LacI to be expressed and repress Plac to translate the genes downstream.

Quantitative data showing the Part or Device function

To test whether red light can regulate P_red or not, we measured the florescence expression of E. coli that were exposed to red light under 37 °C. The figure shows that red light can in fact activate P_red. Colony 5 displays a high normalized expression under red light, suggesting that the biobrick was successfully activated by red light. On the other hand, colony 3 might be mutated, as it shows only little expression.

Figure 2.Colony 5 shows a higher expression as it is activated by red light. Colony might be mutated, since it didn’t seem to be activated.

Positive control: Pcons+mGFP. Negative control:tet 30. Pred is activated by red light and shows strong GFP expression that is close to the expression of the positive control.

Figure 3.Positive control: Pcons + mGFP. Negative control: tet 30. Pred is activated by red light and shows strong GFP expression that is close to the expression of the positive control.

Exposing P_red + mGFP on red light, we measured its fluorecence and compared with the counterpart in the dark.

Figure 4. Comparing the efficiency of P_red under red light and dark. The data indicates that our P_red do actually work

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 1282
  
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 1296
  
• 1000
  COMPATIBLE WITH RFC[1000]