Question

You are able to halt a molecule of RNA polymerase when it’s nearly finished transcribing a gene. How many distinct proteins make up this particular RNA polymerase enzyme and what are they called?

I'm thinking it is core RNA polymerase or RNA polymerase holoenzyme.

Answer 1

Ans. -

RNA polymerase "core" from E. coli consists of five subunits: two alpha (α) subunits of 36 kDa, a beta (β) subunit of 150 kDa, a beta prime subunit (β′) of 155 kDa, and a small omega (ω) subunit.

The RNA polymerase comes across a stop codon on DNA which will recognise the polymerase and hence stop at that point. The stop codons bein UUA UGA UAG. Then 2 types of termination can happen- RHO independent or RHO dependent.

Rho is a protein with a stretch of repeat sequences to recognise the C- rich sequences and forms a round pin like structure to terminate.

RHO independent termination has recognising sequences for C and G on DNA and forms the structure without RHO.

If you have any doubt then mention in comment.