Largest subunit (beta') of bacterial DNA-dependent RNA polymerase (RNAP), N-terminal domain
Beta' is the largest subunit of bacterial DNA-dependent RNA polymerase (RNAP). This family also includes the eukaryotic plastid-encoded RNAP beta' subunit. Bacterial RNAP is a large multi-subunit complex responsible for the synthesis of all RNAs in the cell. Structure studies suggest that RNA polymerase complexes from different organisms share a crab-claw-shaped structure with two "pincers" defining a central cleft. Beta' and beta, the largest and the second largest subunits of bacterial RNAP, each makes up one pincer and part of the base of the cleft. Beta' contains part of the active site and binds two zinc ions that have a structural role in the formation of the active polymerase.
Comment:A complex active site region of DNA-dependent RNA polymerases mainly formed by the two largest subunits that includes Mg binding site, Bridge Helix, Switch and Funnel domains
Jiyao W et al.(2023). "The conserved domain database in 2023.",