The trpL attenuator region mRNA transcript

(a) The trpL attenuator contains 162 nucleotides that include a 14-amino acid coding sequence and four inverted repeat sequences that encode regions 1 through 4 in trpL mRNA. (b–d) Three alternative stem loops can form in trpL mRNA(a) The trpL attenuator contains 162 nucleotides that include a 14-amino acid coding sequence and four inverted repeat sequences that encode regions 1 through 4 in trpL mRNA. (b–d) Three alternative stem loops can form in trpL mRNA

(a) TrpL mRNA End of trpL—>Stop coding sequence Ser & Region 1 U-rich termination sequence (34 stem loop only) Met Gln Thr HT'TH 162 \ Beginning of trpE Beginning of trpL 30 4o coding sequence coding sequence 3; (b) Pause stem loop (1—2 stem loop) (c) Antitermination stem loop (2—3 stem loop) (d) Termination stem loop (3—4 stem loop) 5'!