
The a–h regions are highly conserved among RNA polymerases. The percentages of identical amino acids between the human RNA polymerase III sequence and various eukaryotic largest subunits, the E. coli β′ subunit, and the H. halobium A and C polypeptides within the conserved regions a–hare indicated. The numbers on the right indicate the total length of the polypeptide. P1, P2, and P3 refer to RNA polymerases I, II, and III, respectively.











