Role of leader peptide synthesis in tryptophanase operon expression in Escherichia coli K-12.
نویسندگان
چکیده
We used site-directed mutagenesis to replace the Escherichia coli tryptophanase (tna) operon leader peptide start codon with AUC. This change greatly decreased the uninduced rate of tna operon expression, and it also lowered the response to inducer. We conclude that leader peptide synthesis plays an essential role in tna operon expression.
منابع مشابه
Evidence suggesting cis action by the TnaC leader peptide in regulating transcription attenuation in the tryptophanase operon of Escherichia coli.
Expression of the tryptophanase (tna) operon in Escherichia coli is regulated by catabolite repression and transcription attenuation. Elevated levels of tryptophan induce transcription antitermination at one or more Rho factor-dependent termination sites in the leader region of the operon. Induction requires translation of a 24-residue coding region, tnaC, located in the 319-nucleotide transcri...
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Tryptophanase, encoded by the gene tnaA, is a catabolic enzyme distinct from the enzymes of tryptophan biosynthesis. Tryptophanase synthesis is induced by tryptophan and is subject to catabolite repression. We studied the mechanism of tna operon induction. Mutants with altered rho factor were partially constitutive for tna expression, implicating rho-dependent transcription termination in the c...
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Expression of the degradative tryptophanase (tna) operon of Escherichia coli is regulated by catabolite repression and tryptophan-induced transcription antitermination. In cultures growing in the absence of added tryptophan, transcription of the structural genes of the tna operon is limited by Rho-dependent transcription termination in the leader region of the operon. Tryptophan induction preve...
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ورودعنوان ژورنال:
- Journal of bacteriology
دوره 167 1 شماره
صفحات -
تاریخ انتشار 1986