Part:BBa_K216003

TNT receptor TNT-R3

TNT-R3: a computationally designed receptor binding TNT, made by mutation of the Escherichia coli periplasmic ribose-binding protein: see Looger, L., Dwyer, M.A., Smit, J.J., and Wellinga, H.W. 2003. Computational design of receptor proteins with novel functions. Nature 423, 185-190. This receptor interacts with a hybrid transmembrane protein Trz, created by combining the normal partner of ribose-binding-protein, Trg, with the intracellular part of 2-component sensor protein EnvZ, which normally phosphorylates response regulator protein OmpR, allowing it to activate promoters such as PompC (see Baumgartner, J.W., Kim, C., Brisette, R.E., Inouye, M., Park, C., and Hazelbauer, G.L. 1994. Transmembrane signalling by a hybrid protein: communication from the domain of chemoreceptor Trg thate recognizes sugar-binding proteins to the kinase/phosphatase domainof Osmosensor EnvZ. J. Bacteriol. 176, 1157-1163). To use this receptor, include it in a system with Trz and a reporter gene controlled by PompC.To avoid cross-talk, it may be necessary to use a chassis lacking EnvZ and ribose-binding protein.

Usage and Biology

According to Looger et al (2003), TNT-R3 shows the following affinities for different ligands:

• 2,4,6-trinitrotoluene: 2 nanomomolar
• 1,3,5-trinitrobenzene: 0.1 micromolar
• 2,4-dinitrotoluene: 8.4 micromolar
• 2,6-dinitrotoluene: 15 micromolar

This part is intended to be used with the hybrid signal transduction Trz (BBa_K216004), which has the external region of chemotaxis receptor Trg (which normally interacts with ribose binding protein) fused to the intracellular kinase domain of two-component sensor kinase EnvZ. This allows transduction of ligand detection via activation of a promoter (such as BBa_R0082) controlled by the cognate response regulator OmpR.

Important Note: while we are grateful to Prof. Hellinga for supplying us with the template DNA to make this part, we should note that the results from the 2003 Nature paper have recently been called into question: see these summaries in [http://www.nature.com/news/2009/091012/full/news.2009.998.html?s=news_rss Nature News] and [http://www.the-scientist.com/news/display/56053/ The Scientist]. Essentially, the problem seems to be that the engineered TNT receptors are too unstable to obtain reliable affinity results. However, so far as we know, the in vivo results from the hybrid signal transduction pathway have not been questioned. Since we now have all the parts necessary to repeat these experiments, we are hoping that we will soon be able to confirm the activity of the TNT receptors in vivo.

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
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 372
  Illegal NgoMIV site found at 494
  Illegal NgoMIV site found at 624
  
• 1000
  COMPATIBLE WITH RFC[1000]