PCB 3063 Lecture Notes - Lecture 12: Pribnow Box, Rho Factor, Sigma Factor
RNA polymerase from E. coli is a ...
Holoenzyme
Sigma factor (Sigma subunit)
Finds the start point
- is trans
identifies the right sequence of the promoter
if the sequence is close to perfect it might still bind but it will affect the kinetics of initiation/speed
Rho factor
in some cases it determines termination...........................
Promoter
Is always upstream (5') of the gene.
What is the -35 concensus
TTGACA
What is TATAAT
The pribnow box
E. coli has two concensus promoter sequences
the pribnow box (TATAAT) and TTGACA
What does it mean when we say that the pribnow box is -10 from the initiation site
it is 10 base pairs before the sequence that starts initiation.
Rho-independent termination
the end of the mRNA will have a code sequence that will fold back on itself making a hairpin looking end
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Document Summary
Rna polymerase from e. coli is a Is trans identifies the right sequence of the promoter if the sequence is close to perfect it might still bind but it will affect the kinetics of initiation/speed. Rho factor in some cases it determines termination The pribnow box: coli has two concensus promoter sequences the pribnow box (tataat) and ttgaca. What does it mean when we say that the pribnow box is -10 from the initiation site it is 10 base pairs before the sequence that starts initiation. Rho-independent termination the end of the mrna will have a code sequence that will fold back on itself making a hairpin looking end. Since prok. s don"t have a nucleus there is nothing to separate transcription and translation. Euks. have 3 kinds of rna pols for different types of genes. Caat box affects binding efficiency, -80 postion (euk) 30 , is where rnp(rna pol) binds to dna (euk)