The sequence of the distal end of the E. coli ribosomal RNA rrnE operon indicates conserved features are shared by rrn operons.

The 1440 nucleotides of the distal region of the E. coli ribosomal RNA operon found on the lambda aroE transducing phage has been sequenced. We show that the lambda aroE hybrid rrn operon ends after a solitary 5S RNA gene with rrnE distal sequence. A single terminator structure of dyad symmetry followed by a run of six T's have been identified and compared to other sequenced rrn terminator hairpins. Immediately adjacent to the hairpin is a region of interrupted but conserved sequence that is shared by rrnE, rrnB and rrnD. An open reading frame of 127 amino acids abuts the terminator structure. Another open reading frame of 147 amino acids is found on the opposite strand several hundred nucleotides downstream.