Lecture 4 - Transcription Flashcards
1
Q
Sub-units of the E.Coli RNA polymerase “holoenzyme” (5)
A
α2ββ’ core
ω
α2ββ’σ holoenzyme
2
Q
α…
A
Is required for enzyme assembly (two copies per holoenzyme).
3
Q
β…
A
Forms a pincer with β’ that acts as a DNA clamp; target of rifampicin.
4
Q
β’… (3)
A
- Forms a pincer with β that acts as a DNA clamp.
- Provides a conserved NADFDGD motif essential for
catalysis. - The three aspartates in the motif co-ordinate Mg2+ and
are essential for phosphodiester bond formation.
5
Q
ω…
A
Helps fold the β’ subunit before recruiting it to α2β.
6
Q
σ…
A
Is responsible for DNA binding specificity.