DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. MVREEVAGSTQTLQWKCVESRVDSKRLYYGRFILSPLRKGQADTVGIALRRALLGEIEGTCITRAKFGSVPHEYSTIAGIEESVQEILLNLKEIVLRSNLYGVRDASICVKGPRYITAQDIILPPSVETVDTAQPIANLTEPIDFCIDLQIKRDRGYQTELRKNYQDGSYPIDAVSMPVRNVNYSIFSCGNGNEKHEILFLEIWTNGSLTPKEALYEASRNLIDLFLPFLHAEEEGTSFEENKNRFTPPLFTFQKRLTNLKKNKKGIPLNCIFIDQLELTSRTYNCLKRANIHTLLDLLSKTEEDLMRIDSFRMEDRKHIWDTLEKHLPIDLLKNKLSF 339 RPOA_HORVU DNA-directed RNA polymerase subunit alpha rpoA Plastid-encoded RNA polymerase subunit alpha