Difference between revisions of "Part:BBa K845009"

Latest revision as of 13:54, 30 September 2012

paraBAD_gfp_cyaA

In order to create a biological AND gate the 2012 Grenoble team worked on the cAMP-CRP complex and arabinose inductible promoter.

We assembled this AND gate a reporter and a enzyme (cyaA gene) to create an amplification loop.

Usage and Biology

paraBAD is a promoter which can be activated by 2 molecules : CRP-cAMP complex and the AraC protein. It has two states; in absence of L-arabinose the paraBAD promoter is repressed by AraC, whereas the paraC promoter is activated (unless an excess of AraC is present). In presence of L-arabinose and the CRP-cAMP complex, the promoter is activated thus enabling the transcription of the downstream elements. This AND gate provides a filter to biological noise.

In Escherichia coli, cAMP is involved in carbon catabolite repression [1] and binds to the cAMP receptor protein (CRP). The corresponding complex (CRP-cAMP) is a transcriptional factor controlling the expression of more than 220 operons [2]. It has been known for a long time that E. coli actively exports cAMP into the growth medium [3][4]. The transcription of the cyaA gene and the crp gene is negatively regulated by CRP-cAMP [5] [6]. The translation of adenylate cyclase mRNA is ineffective as to prevent excessive synthesis of adenylate cyclase. This can be attributed to the fact that overproduction of cAMP is lethal to Escherichia coli possibly due to an accumulation of methylglyoxal [7] [8]. As we want to use paraBAD like an AND Gate and because high a concentration of cAMP is lethal for E. Coli we make our device in a BW25113 ΔcyaA.

http://www.uniprot.org/uniprot/P00936

http://ecocyc.org/ECOLI/NEW-IMAGE?type=GENE&object=EG10170

Sequence and Features