Abstract
Expression of the tryptophanase operon of Escherichia coli is regulated by catabolite repression and tryptophan-induced transcription antitermination. An induction site activated by L-tryptophan is created in the translating ribosome during synthesis of TnaC, the 24-residue leader peptide. Replacing the tnaC stop codon with a tryptophan codon allows tryptophan-charged tryptophan transfer RNA to substitute for tryptophan as inducer. This suggests that the ribosomal A site occupied by the tryptophanyl moiety of the charged transfer RNA is the site of induction. The location of tryptophan-12 of nascent TnaC in the peptide exit tunnel was crucial for induction. These results show that a nascent peptide sequence can influence translation continuation and termination within a translating ribosome.
Original language | English (US) |
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Pages (from-to) | 1864-1867 |
Number of pages | 4 |
Journal | Science |
Volume | 297 |
Issue number | 5588 |
DOIs | |
State | Published - Sep 13 2002 |
Externally published | Yes |
ASJC Scopus subject areas
- General