BCH311H1 Lecture 8: BCH311 Notes III (Andreopoulos' Lecs)
15 Sep 2015
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Document Summary
Focus in prokaryotes: promoter binding and initiation, elongation of nascent rna transcript, termination at end of gene. Focus in eukaryotes: use three different polymerases to transcribe their rnas, highly regulated by binding of transcription factors, primary transcripts are extensively modified. Prokaryotic and eukaryotic rna polymerase: overall structure quite similar, rna synthesis is in 3 stages: initiation, elongation, termination. Initiation sites/promoters cis acting elements: unwinds dsdna, correct ribonucleoside triphosphate selection unidirectional/processive, termination, activation/repression transcription factors, fundamental reaction. Rnap active site: similar to dnap: 2 mg2+: one inside active site and the other comes in with the ribonucleotide, 3 key amino acids asp = negative aa; coordination between mg2+ and asp. Identification of promoter sequences used by rnap: radioactively label a strand dnase i random cleavage along strand denature dsdna: sets of labeled fragments run all tubes on gel to generate different sized fragments.
