Biochemistry 2280A Lecture Notes - Lecture 17: Tryptophan, Sigma Factor, Nucleosome
22 Jan 2018
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Topic 17 & 18: prokaryotic and eukaryotic transcription and gene regulation. Steps where regulation can occur: transcription (initiation elongation termination) Consensus sequence: most frequent base at a position in a group of functionally related dna elements (none of the elements actually have to be the consensus sequence) Bacterial operon structure: promoter about 100 bp (+1 site is where transcription starts, -10 & -35 are consensus sequences) Bacterial rna polymerase: makes rna using a dna template and ntps as substrates: multi-su(cid:271)u(cid:374)it e(cid:374)z(cid:455)(cid:373)e (cid:894)(cid:272)ore e(cid:374)z(cid:455)(cid:373)e (cid:272)a(cid:374) (cid:373)ake rna i(cid:374) test tu(cid:271)e (cid:271)ut does(cid:374)"t re(cid:272)og(cid:374)ize pro(cid:373)oters . Need the sigma subunit to recognize promoters: sigma recognizes -10 and -35 areas and then can bind to the promoter (dna/protein interaction) **there is more than one sigma factor, each one recognizes different promoter sequences** Rnap holoenzyme binds the promoter through interactions at -10 and -35 sites (closed complex)
