Question

Which DNA sequence element serves as the primary recognition site for the sigma factor in bacterial promoters?

Options

• The terminator sequence at the end of the gene

• The –35 region only

• The –10 region (Pribnow Box) only

• The ribosome binding site downstream of the promoter

Answer 1

The –35 region is important for initial recognition by the sigma (σ) factor during bacterial promoter binding. While the –10 region (Pribnow Box) is crucial for DNA melting due to its A-T richness, it is the –35 region that the σ factor primarily recognizes first. Both regions are necessary for efficient promoter recognition and initiation complex formation.