Difference between revisions of "Part:BBa K1173501"

Latest revision as of 02:32, 5 October 2013

CcaS, CcaR, PcpcG2, cI(lambda), magenta

This is a composite part which is responsive to green light and controls the production of a magenta pigment. CcaS is a trans-membrane protein which responds to green light by phosphorylating CcaR when green light is present. CcaR-P then binds to a specific promoter (BBa_K592003), which allows the transcription of the cI protein. This in turn binds to a specific promoter, which prevents the transcription of a gene coding for a magenta pigment (BBa_K592012). Overall, this means that exposure of the cells to green light will halt the synthesis of magenta pigment. Inversely, lack of exposure to green light will allow the synthesis of magenta pigment.

PLEASE NOTE that all of the coding sections within this part are His-tagged (CcaS, CcaR, cI repressor protein and cyan pigment), which does not appear to interfere with the system.

ALSO be aware that the diagram of this BioBrick DOES NOT accurately represent it's sequence. The regions coding for CcaR and magenta have been REVERSE COMPLEMENT-ED. We also had to deconstruct BBa_C0051, as we needed the cI promoter to go before the magenta pigment.

Usage and Biology

The plate on the left was put in a static incubator containing a light box and was left to grow overnight. The plate on the right was grown overnight in an incubator which was blacked out. You can see the difference in colour, given by different expression of the eforred protein which is controlled by the CcaS and CcaR light sensitive system.

The image to the left shows liquid cultures of bacteria with the green light pathway integrated into the DNA. The light each of the liquid cultures received was varied so that the far left vial had no light and the far right vial had a high intensity of light, with the amount of light exposed to the vial increases incrementally from left to right. Here you can see that there is an intensity of light to which there is a drastic change in the amount of colour seen.

The graph to the left shows the development of the pigment K592012 over time whilst the cells are grown in the dark. The liquid cultures of E. coli were grown up in a shaking incubator in the dark overnight and then samples were taken at intervals before being put in a 96 well plate for the absorption to be measured.

Sequence and Features