title: Instruction of translating ribosome by nascent peptide.
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.
authors.affiliation: Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Gong
authors.forename: Charles
authors.initials: C
authors.lastname: Yanofsky
mesh_terms: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D002701:Chloramphenicol / Q000494:pharmacology; D003062:Codon; D018388:Codon, Terminator; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D009876:Operon; D010443:Peptide Chain Termination, Translational; D010458:Peptidyl Transferases / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects; D012329:RNA, Bacterial / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012270:Ribosomes / Q000378:metabolism*; D013698:Templates, Genetic; D014364:Tryptophan / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D014368:Tryptophanase / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D003062:Codon; D018388:Codon, Terminator; D029968:Escherichia coli Proteins; D012329:RNA, Bacterial; D012346:RNA, Transfer, Amino Acyl; C081473:tnaC protein, E coli; D002701:Chloramphenicol; D014364:Tryptophan; D012343:RNA, Transfer; D010458:Peptidyl Transferases; D014368:Tryptophanase; C100305:kasugamycin