DNA-dependent RNA polymerase (RNAP) catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. a ribonucleoside 5'-triphosphate + RNA(n) = diphosphate + RNA(n+1) Binds 1 [3Fe-4S] cluster. Part of the RNA polymerase complex. Belongs to the archaeal Rpo3/eukaryotic RPB3 RNA polymerase subunit family. X-ray crystallography in other archaea shows this protein binds a 3Fe-4S cluster, although a 4Fe-4S cluster has been suggested to be present in this protein.