Part:BBa_K1031441

J23106-HcaR

For detailed information concerning HcaR, please visit 2013 Peking iGEM Biosensor HcaR

Characterization

In order to fine-tune the performance of HcaR biosensor, we constructed a library of Pc constitutive promoters, collocating with a library of RBS (Ribosome Binding Site) at different intensity. BBa_K1031441 is composed of three elements, the constitutive Pc promoter J23106[1], coding sequence of HcaR and terminator B0015[2]. (Fig 1).

Fig 1 Construction of biosensor circuit Ph/J23106-HcaR. The orange arrowheads represent promoters, RBS is shown as a green oval, and the red circle stands for B0015 terminator.

Sequence and Features

Sequence and Features

Assembly Compatibility:

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

  Illegal NheI site found at 7
  Illegal NheI site found at 30
  
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 892
  Illegal AgeI site found at 565
  
• 1000
  COMPATIBLE WITH RFC[1000]

Data shown

Tuning

Induction ratio of HcaR biosensor library test utilizes different Pc promoters, collocating with RBSs (Ribosome Binding Sites) at different intensity to optimize the performance of HcaR. The first three lines are data for HcaR biosensor circuit adopting Pc J23106 in collocation with RBS B0031, B0032 and B0034 respectively. The dashed box refers to data for Ph/J23106-HcaR biosensor circuit (Fig 2) in collocation with RBS B0032, which obtains the optimal performance among them.

Fig 2 Induction ratio of HcaR biosensor library test. Horizontal axis stands for different HcaR biosensor with Pc promoters of different strength. The expression strength of these constitutive promoters, J23113, J23109, J23114, J23105, J23106 is 21, 106, 256, 623, and 1185, respectively, according to the Parts' registry. PPA was tested following Test Protocol 1 [http://2013.igem.org/Team:Peking/Team/Notebook/Protocols] as inducer. Vertical axis represents the ON-OFF induction ratio. The dashed box refers to performance for Ph/J23106-HcaR biosensor adopting RBS B0032.

ON/OFF test

The best performed biosensor Ph/J23106-HcaR with RBS B0032 is then subjected to the On-Off test about 78 aromatics according to protocol 1[http://2013.igem.org/Team:Peking/Team/Notebook/Protocols]. Results showed that HcaR worked as a specific sensor to PPA (Fig 4).

Fig 3 Results of On-Off test about biosensor HcaR. HcaR specifically responds to PPA (1000 μM) with the induction ration over 2.

Dose-response curve

PPA was used to test dose-response curve of Ph/J23106-HcaR. Two biosensor circuits adopting RBS B0032 and B0034 are tested respectively.(Fig 3)

Fig 3 Dose response curve of biosensor circuit Ph/J23106-HcaR induced by PPA. X-axis stands for concentration gradient of inducers at 1µM, 5µM, 10µM, 50µM, 100µM, 500µM and 1000µM. Y-axis shows induction ratio reflected via fluorescence intensity.Two biosensor circuits adopting B0032 and B0034 are shown in different color intensity.