cd02733

Largest subunit (Rpb1) of eukaryotic RNA polymerase II (RNAP II), N-terminal domain; The two largest subunits of RNA polymerase II (RNAP II), Rpb1 and Rpb2, form the active site, DNA entry channel and RNA exit channel. RNAP II is a large multi-subunit complex responsible for the synthesis of mRNA in eukaryotes. RNAP II consists of a 10-subunit core enzyme and a peripheral heterodimer of two subunits. Structure studies suggest that RNAP complexes from different organisms share a crab-claw-shape structure. In yeast, Rpb1 and Rpb2, each makes up one clamp, one jaw, and part of the cleft. Rpb1_N contains part of the active site, forms the head and core of the one clamp, and makes up the pore and funnel regions of RNAP II.