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Team:Edinburgh/Bacterial/Green light sensor
From 2010.igem.org
If we are to make a complete repressilator, we will need a green light-sensing BioBrick to go with the red and blue. To our knowledge, there has been no green light sensor successfully used in E. coli. Tokyo-Nokogen 2009 attempted to make a green light sensor but couldn't make it work, due to problems with the BioBricks stored in the Registry.
Tokyo-Nokogen's design adapted the red light sensor designed by Austin 2005 to sense green light, by replacing the Cph1 domain of the protein (which reacts to red light) with the light sensing domain of Ccas (which senses green light). However, the second part of the protein is the inner membrane region of EnvZ, which duplicates with the red sensor.
With this system, OmpR will be phosphorylated by both green light and red light sensors, and the cell would be colour blind. While CcaS would be a good protein to use for the purpose of sensing green light, we therefore need to link it to a different two-component system if we want to make a separate green light sensor. One possibility is to copy the method that was used to make lovTAP. This would be better since it is more direct (the light sensor binds the DNA directly and represses it) than Cph8 which represses its target through the EnvZ transduction pathway (via OmpR).
Problems:
BioBricks:
