Largest subunit (beta') of Bacterial DNA-dependent RNA polymerase (RNAP), C-terminal domain
Bacterial RNA polymerase (RNAP) is a large multi-subunit complex responsible for the synthesis of all RNAs in the cell. This family also includes the eukaryotic plastid-encoded RNAP beta" subunit. Structure studies suggest that RNAP complexes from different organisms share a crab-claw-shape 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. The C-terminal domain includes a G loop that forms part of the floor of the downstream DNA-binding cavity. The position of the G loop may determine the switch of the bridge helix between flipped-out and normal alpha-helical conformations.
Comment:Bacterial RNAP beta' and beta subunits correspond to the Rpb1 (largest) and Rpb2 (second largest) subunits, respectively, of yeast RNAPII.
Structure:1HQM; Interface between the beta' (1HQM_D) and beta (1HQM_C) subunits of Thermus aquaticus RNAP; defined using 3.5A contacts - View structure with Cn3D
Structure:2O5I; Interface between the beta' (2O5I_D) and beta (2O5I_C) subunits of Thermus thermophilus RNAP; defined at 3.5A contacts - View structure with Cn3D
Jiyao W et al.(2023). "The conserved domain database in 2023.",