BIO230H1 Lecture Notes - Lecture 3: Lambda Phage, Helix-Turn-Helix, Prophage
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BIO230H1 Full Course Notes
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Document Summary
Continued : recap of prokaryotic gene regulation, bacteriophage lambda, synthetic biology, transcription attenuation. Tryptophan repressor contains a helix turn helix. Binds in a major groove of dna double helix. Competition between rnap and repressor protein for promoter binding. Activator protein recruits rnap to the promoter to activate transcriptions. Gene regulatory elements are typically close to the transcriptional start site of prokaryotic genes. In this case, regulatory element are very close to transcription start site. But regulatory elements can also be found: Dna looping allows ntrc to directly interact with rna polymerase to activate transcription from a distance. Attach to bacterial cell and inject its dna, then undergo one of two life cycles. Positive and negative regulatory mechanisms work together to regulate the lifestyles of bacteriophage lambda. Bacteriophage lambda can exist as one of two states in bacteria. Prophage pathways (favorable condition): lambda dna integrate into the bacterial genome and replicate along with the host chromosome.
