Final answer:
The Pribnow box's sequence TATAAT is optimal for sigma factor binding during transcription initiation in E. coli. A deviation from this sequence, like TATACT, could weaken this interaction and potentially result in less efficient transcription initiation. However, having the consensus sequence doesn't ensure transcription, as other regulatory factors are also involved.
Step-by-step explanation:
In E. coli, the consensus sequence for the Pribnow box (the -10 sequence) is TATAAT, which indicates that this sequence will be the one most readily recognized and bound by the sigma factor during the initiation of transcription.
The Pribnow box is an A-T rich consensus sequence found in prokaryotic promoters, where it plays a crucial role in the binding of RNA polymerase and the initiation of transcription. Variations in this consensus sequence, such as TATACT, may result in a weaker binding affinity for the sigma factor, potentially leading to less efficient transcription initiation for that promoter. However, the presence of the consensus sequence alone does not guarantee that the sequence will always be transcribed into RNA as transcriptional regulation involves other elements and factors as well.