FIG. 1.

(A) Nucleotide sequence of a segment of the tna leader transcript (from nts +1 to +115) followed by the fused nucleotide sequence containing the rpoBC terminator. The nucleotide sequence at the distal end of the tnaC coding region that forms the pause I hairpin structure and a portion of the Rho factor utilization (rut′) site that is rich in C residues located in the vicinity of the tnaC stop codon are indicated. The rpoBC terminator sequence including a segment of the rpoC coding sequence is underlined. Note that there are predicted hairpin structures that might form in the segment of rpoBC coding sequence (underlined twice); the free energy of formation of each structure is shown. (B) Predicted RNA hairpin structure (pause I) formed by the end of the transcript of the tnaC coding region. The free energy of formation of this structure is −9.6 kcal/mol.