BIO230H1 Lecture Notes - Lecture 3: Positive Feedback, Tryptophan, Allolactose

• School: UTSG
• Department: Biology
• Course: BIO230H1
• Professor: Darrell Desveaux Tony Harris

Document Summary

Thursday, september 14th, 2017 1pm-2pm (alberts et al. Lecture 3 outline: review of prokaryotic gene regulation, bacteriophage lambda, synthetic biology, transcription attenuation. The tryptophan repressor contains a helix-turn-helix dna binding motif (most common dna-binding motif). Tryptophan repressor: binds in major groove of dna double helix, motif fits into major groove of dna and binds, allowing transcriptional regulator to bind as well. Tryptophan binding induces: conformational change, fits in major groove. Trp repressor (dimer with two motifs that are too close together to fit into major grooves: when bound, conformational change (for both cap and trp) to increase affinity, so they can fit into major grooves. Positive regulation is also simple: gene regulation in prokaryotes is simple activators and repressors influence rna polymerase directly to carry out transcription. Gene regulatory elements are typically close to the transcriptional start site of prokaryotic genes. Lac operon = set of genes driven by one promoter, all found on one rna molecule (prokaryotic feature)