Flashcards in Lecture 7 Deck (98)
Messenger RNAs (mRNA)
encode the amino acid sequences of
all the polypeptides found in the cell
Transfer RNAs (tRNA)
match specific amino acids to triplet
codons in mRNA during protein synthesis
Ribosomal RNAs (rRNA)
is the RNA component of the
ribosome, interact with tRNA during translation
Micro RNA (miRNA)
post-transcriptionally regulate the
expression of genes, by binding to mRNA nucleotide sequences
RNA can be catalytic
Elongates an RNA strand in the 5'-3' direction, using the 3' hydrozyl to attack the a-phosphorous atom in the incoming nucleotide and release PPi
In Transcription: Where is the non-template strand traversing out of?
In Transcription: where is the template stand running through?
DNA/RNA hybrid size
8 bp in size
Transcription: NTP channels
Sampled in the active site (need right base matching the template)
-Right bases will incorporate
-Wrong bases will have poor Kd and get kicked out of the way
Elongation: Footprint size
35 bp worth of DNA
Initiation: Footprint Size
100 bp- when RNA polymerase is first associated with DNA
What is a footprint?
Extent of how much RNA polymerase covers on DNA
What is a template strand?
DNA Strand that serves as the template for RNA synthesis
-Other strand is called CODING because it has the same sequence as the newly made RNA molecule
Elongation occurs as a rate of...
RNA Polymerase Core Subunits
a,a,B,B',w (omega), o(omega)
RNA Polymerase: Sigma Subunit
-Directs enzyme to the promoter
-The chaperone-takes the polymerase to the right promoter to the the right place where it needs to be polymerized
-Different sigmas can be used to turn on different genes all within same Core! To coordinate gene expression. they recognize own promoters
RNA Polymerase: alpha Subunit
(2) alphas. Functino is assembly and binding to UP elements (sequence upstream of promoter)
RNA Polymerase: Beta Subunit
Main catalytic subunit
RNA Polymerase: B' Subunit
Subunit responsible for DNA-building
RNA Polymerase: Omega (w) Subunit
appears to protect the polymerase from denaturationg
-Not catalystic role
-If you take away the RNA polymerase, dalls apart faster
Does UP element have specificity?
YES that interact with ALPHA subunits and Kd goes down when binding is favorable
Does RNA polymerase have proofreading ability?
NO so it makes mistakes every 10^4-10^5 nucleotides
-mistakes in RNA synthesis are not critical because many RNA copes are made from a single gene and they are rapidly degraded/ replaced
RNA polymerase binds to how many nucleotides?
100- stretching from 70 bp upstream (negative numbers) of the strat site and 30 bp downstream (positive numbers)
Start site is the
FIRST RNA RESIDUE that is incorporated in the RNA (+1 site)
Important promoter regions in E.Coli
-10 and -35
TATA sequence is found on -10 with a second sequence on -35.
-Sigma70 subunit binds to these seuqnces