Largest subunit (RPC1) of eukaryotic RNA polymerase III (RNAP III), N-terminal domain
Rpc1 (C160) subunit forms part of the active site region of RNAP III. RNAP III is one of the three distinct classes of nuclear RNAP in eukaryotes that is responsible for the synthesis of tRNAs, 5SrRNA, Alu-RNA, U6 snRNA genes, and some others. RNAP III is the largest nuclear RNA polymerase with 17 subunits. Structure studies suggest that different RNA polymerase complexes share a similar crab-claw-shaped structure. The N-terminal domain of Rpb1, the largest subunit of RNAP II in yeast, forms part of the active site, making up the head and core of the one clamp, as well as the pore and funnel structures of RNAP II. The strong homology between Rpc1 and Rpb1 suggests a similar functional and structural role.
Comment:A complex active site region of >500 amino acids of DNA-dependent RNA polymerase II forms mainly by Rpb1 and Rpb2 subunits, including Mg binding site, Bridge Helix, Switch and Funnel domains
Comment:Study of structural model homology of RNA polymerase (Pol) III indicate similarity of the core fold and the active center of Pol III and Pol II
Comment:Defined by comparison to related structures
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