DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Second largest core component of RNA polymerase I which synthesizes ribosomal RNA precursors. Proposed to contribute to the polymerase catalytic activity and forms the polymerase active center together with the largest subunit. Pol I is composed of mobile elements and RPA2 is part of the core element with the central large cleft and probably a clamp element that moves to open and close the cleft.
DNA-directed RNA polymerase I 135 kDa polypeptide; DNA-directed RNA polymerase I 135kDa polypeptide; DNA-directed RNA polymerase I subunit RPA2; POLR1B; polymerase (RNA) I polypeptide B; polymerase (RNA) I polypeptide B, 128kDa; polymerase (RNA) I subunit B; RNA polymerase I subunit 2; RPA135