BIO 3124 Lecture Notes - Lecture 6: Corepressor, Repressor, Operon
20 Dec 2018
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Describe the difference between negative and positive gene regulation in prokaryotes (transcription) Enzyme made only when substrate is present affect degradative (catabolic) enzymes inducers and corepressors bind to dna-binding protein which affects transcription the repressor protein is active in the absence of the inducer, completely blocking transcription. When the inducer is added, it combines with the repressor protein and inactivates it; inhibition is overcome and transcription can proceed. Compare and contrast differences and similarities in the transcriptional control mechanisms between bacteria, archaea and eukarya. Bacteria use dna-binding proteins that either block rna polymerase activity (repressor proteins) stimulate rna polymerase activity (activator proteins) Archaea: can act as both repressor and activator repressor proteins either block the binding of rna polymerase itself or block the binding of proteins that are required for rna polymerase to bind to the promoter. Some act as activators by recruiting the binding proteins to the promoter and facilitate transcription.
