Part:BBa_I752000

Riboswitch(theophylline)

The riboswitch changes conformation depending on the presence of theophylline. In the absence of theophylline, the switch prevents the binding of the mRNA to the ribosome whilst in the presence of said chemical, the conformation changes and the mRNA behind the switch can then be expressed.

The RNA secondary structure of the Theophylline Riboswittch with a Theophylline molecule binding to it.

This Theophylline Riboswitch reveals an RBS on the addition of Theophylline. The RBS is hidden within the secondary structure when there is no Theophylline around. NYMU-Taipei iGEM10 used Part:BBa_K411003 to test this part. The [http://2010.igem.org/Team:NYMU-Taipei/Experiments/Speedy_switch results] confirmed that the theophylline riboswitch works and has an increased rate of induction when the concentration of Theophyilline is increased. The results also show that the Theophylline riboswitch is leaky in E. coli DH5α.

Relative fluorescence of the Theophylline riboswitch with respect to no Theophylline added verses the different amounts concentrations of Theophylline. The x axis is in the scale of log10 of the concentration in uM.

From this graph, we observe three things:
* When the concentration of Theophylline is log10(4000uM)=3.60, there is a 2.2x fold increase in downstream translation compared to no Theophylline added.
* There is a positive correlation between the amount of Theophylline added and the strength of the induction until log10(4000uM)=3.60.
* After log10(4000uM)=3.60, there is a decrease in the strength of the induction as Theophylline is poisonous to E. coli and after log10(5000uM)=3.7, the E. coli is unable to handle it.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]