Modelling the repression of the promoter
IPTG is an inducer which binds to LacI.
LacI is a repressor that is constitutively expressed. It binds to
the promoter preventing the promoter from expressing an output, in
this case GFP.
In the absence of IPTG , LacI is constitutively expressed. Hence
the constitutive expression model from the previous
characterisation step can be assumed. At the same time, it can
bind to the promoter to repress it.
Evolution of LacI concentration
The repressor only binds to the promoter when it is in its unbound
form.
Evolution of promoter concentration
Evolution of the promoter-LacI complex
Evolution of GFP
dGFP[GFP] is the basal rate of GFP. This is caused by
the leakiness of the LacI-PLac complex when LacI does not repress
the promoter completely.