https://www.ncbi.nlm.nih.gov/Structure/pdb/5NSS
5NSS: Cryo-EM structure of RNA polymerase-sigma54 holoenzyme with promoter DNA and transcription...
DNA-directed RNA polymerase subunit alphaDNA-directed RNA polymerase subunit betaDNA-directed RNA polymerase subunit beta',DNA-directed RNA polymerase subunit...