Repressor always bound to operator

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Repressor always bound to operator

Post by amoeba271 » Tue Nov 24, 2009 6:00 am

In a normally functioning lac operon, in prokaryotes, repressor protein binds the operator only when lactose concentration is high. However, consider a mutant where the repressor always binds operator. What is a mechanism for having lac Z transcribed only when needed? (i.e. when lactose concentrations are low)

I cannot think of a solution to this because the lac I sequence that codes for repressor is behind the operator sequence so the repressor protein will always be transcribed.

The green protein in the diagram is the repressor protein.

Do you know of any mechanism that allows transcription of lac Z gene even when repressor is always bound to operator sequence?
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Inland Taipan
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Post by MrMistery » Wed Nov 25, 2009 3:05 am

no. repressor always bound => RNA polymerase cannot bind to promoter. If they are asking you for a mechanism to transcribe the lacZ gene in the presence of such a super-represor, they are basically asking you to make stuff up, because in real life that just doesn't happen
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Inland Taipan
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Post by mith » Wed Nov 25, 2009 8:02 pm

stochastics lol
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