Question

Which statement is FALSE?

A. If domain 1.1 is deleted, sigma will bind promoter sequence.

B. Domain 1.1 is blocking the region where DNA is located when the promoter is melted.

C. Domain 1.1 prevents sigma from binding promoter without first binding the RNAP core.

D. Domain 1.1 helps melt the promoter sequence and create an open promoter complex.

Answer 1

The false statement is D, as domain 1.1 of the sigma factor does not help in melting the promoter sequence; it inhibits sigma from binding to the promoter unless it is associated with the RNA polymerase core.

Step-by-step explanation:

The statement that is FALSE among the given choices is: D. Domain 1.1 helps melt the promoter sequence and create an open promoter complex. In the context of bacterial transcription, the sigma factor (σ) is responsible for the recognition of the promoter sequence and the initiation of transcription.

Domain 1.1 of the sigma factor acts as an autoinhibitory region that blocks the binding of the sigma factor to the promoter DNA unless it is associated with the RNA polymerase core enzyme. Once the sigma factor is bound to the RNA polymerase core, this interaction leads to the necessary conformational changes, allowing domain 1.1 to move out of the way and enable the sigma factor to bind to the promoter sequence.

The A-T-rich -10 region of the promoter, with the consensus sequence TATAAT, facilitates the unwinding of the DNA template for transcription initiation.