Question

How is the bacterial core promoter recognized by RNAP?

A. Discriminator element binds subdomain 3.2 and this helps melt the promoter

B. Strong contacts between sigma and alpha CTDs contribute to promoter recognition

C. Upstream promoter element recruits 2 copies of omega subunit

D. Through contacts of sigma subdomains 2.4/2.3 and 4.2 and cis-acting promoter elements

Answer 1

The bacterial core promoter is recognized by RNA polymerase through contacts of sigma subdomains 2.4/2.3 and 4.2 and cis-acting promoter elements. The -10 and -35 regions upstream of the initiation site in the promoter contain specific consensus sequences that are recognized by sigma subunits. Once sigma binds to these consensus sequences, the rest of the RNA polymerase enzyme complex binds to the promoter and initiates transcription.

Step-by-step explanation:

The bacterial core promoter is recognized by RNA polymerase through contacts of sigma subdomains 2.4/2.3 and 4.2 and cis-acting promoter elements. The -10 and -35 regions upstream of the initiation site in the promoter contain specific consensus sequences that are recognized by sigma subunits. The -10 sequence, also known as the TATA box, has the consensus sequence TATAAT, while the -35 sequence has the consensus sequence TTGACA. Once sigma binds to these consensus sequences, the rest of the RNA polymerase enzyme complex binds to the promoter and initiates transcription.