Difference between revisions of "Part:BBa K2012023"

Promoter cpcG2 is a 238bp green-light activated promoter from the genome of Synechocystis PCC6803. We tested the efficiency of the promoter by measuring the fluorescence of output sfGFP when bacteria are illuminated with green, red or no light. (For more detail, please view our wiki: http://2016.igem.org/Team:HZAU-China/Experiments)

 

Figure 1. Comparison of sfGFP fluorescence of CcaS-CcaR system under green light, red light and darkness.

 

As is shown in Figure 1, in E.coli strain JT2, PcpcG2 produces 266.0 ± 19.3 and 509.0 ± 55.4 au of sfGFP in red and green light, corresponding to 1.91 ± 0.34-fold activation, demonstrating that PcpcG2 is functionally regulated by light, green-activated and red-repressed.

 

However, the figure also shows that that leaked expression is severe in dark surroundings. To better respond to red and green light, we optimized the promoter by refactoring it and created an innovative promoter, PcpcG2-172, with the truncation of a constitutive promoter within the cpcG2 promoter (BBa_K2012015. For more detail, please view our wiki: http://2016.igem.org/Team:HZAU-China/Experiments)

Improve by HZAU-China 2017, designed by Chu Pan

This year we improved the CcaS-CcaR system used in last year. By changing the RBS strength of CcaR, we optimized the expression of sfGFP from 2-fold variance up to 3-fold variance.

[[File:T--HZAU-China--improve.png|200px|thumb|left|The RBS of CcaR is modified]]