Final answer:
The Sigma (σ) subunit confers specificity to transcription in E. coli polymerase.
Step-by-step explanation:
The subunit of the E. coli polymerase that confers specificity to transcription is the Sigma (σ) subunit.
The polymerase core enzyme is composed of four subunits: α, α, ß, and ß'. These subunits are responsible for assembling and disassembling during transcription. The σ subunit, on the other hand, is involved only in transcription initiation and plays a crucial role in determining the correct initiation site for mRNA synthesis.
Without the σ subunit, the core enzyme would transcribe from random sites, producing mRNA molecules that specified protein gibberish.