FAQ: What are the major functions of these subunits?

The major functions of the subunits are:
  • The β' subunit contains part of the active center responsible for RNA synthesis.
  • The β subunit contains the rest of the active center responsible for RNA synthesis.
  • The α subunit is present in two copies per molecule of RNA Polymerase. The α subunit contains determinants for assembly of RNA Polymerase and for interactions with regulatory factors.
  • The small ω subunit facilitates assembly of RNA Polymerase and stabilizes assembled RNA Polymerase.
  • Sigma factors, upon associating with the core enzyme, increase specificity for its promoters and allow transcription to initiate at correct sites.