Team:Edinburgh/biology(tntsensing)

Personal note

One of the reasons for studying biology for me has always been that scientific knowledge is power. The exhilarating and empowering IGEM experience has finally helped me understand that I really am one of the key holders to progress.

Julia

The moment a landmine encounters soils, it leaks TNT (Jenkins et al., 2001). TNT will be detected by a computationally designed synthetic receptor, TNT.R1 (Looger et al., 2003). Since TNT.R1 is derived from ribose-binding protein and wild-type E. coli swims towards ribose, we hypothesize that E. coli cells expressing TNT.R1 will chemotaxi towards TNT. To verify this we performed a chemotaxis experiment. To see the experimental results in detail please click here.

Upon interaction with TNT, the receptor (BBa_xxxx) will undergo a conformational change, allowing it to interact with Trg-EnvZ (a.k.a Trz) fusion protein (BBa_xxxx). Previously, Trg-EnvZ was entered into the registry, unfortunately, the sequencing results were inconsistent. Furthermore, we failed to revive stabs received from the registry. As such, we contacted Dr Hazelbauer and colleges who kindly provided us with the plasmid carrying the fusion protein (Baumgartner et al., 1994).

Subsequently, Trg-EnvZ also undergoes conformational change and autophosphorylates. Eventually, it phosphorylates the secondary messenger ompR, and phosphorylated omp-R activates the ompC promoter (BBa_R0082).

Activation of PompC will result in upregulation of enhanced yellow fluorescent protein (eyfp) and onr. Onr encodes PETN reductase, a nitroreductase from Enterobactor cloacae (Accession #: U68759, BBa_xxxx). PETN reductase will reduce TNT to nitrites (French et al., 1998) that would feed into the nitrite/nitrate detection system.

Edinburgh University iGEM Team 2009