Operon that codes for the components for production of tryptophan
Structure of the trp operon
The trp operon is a group of genes that are transcribed together, encoding the enzymes that produce the amino acid tryptophan in bacteria. The trp operon was first characterized in Escherichia coli, and it has since been discovered in many other bacteria.[1] The operon is regulated so that, when tryptophan is present in the environment, the genes for tryptophan synthesis are repressed.
The trp operon contains five structural genes: trpE, trpD, trpC, trpB, and trpA, which encode the enzymes needed to synthesize tryptophan. It also contains a repressive regulator gene called trpR. When tryptophan is present, the trpR protein binds to the operator, blocking transcription of the trp operon by RNA polymerase.
This operon is an example of repressible negative regulation of gene expression. The repressor protein binds to the operator in the presence of tryptophan (repressing transcription) and is released from the operon when tryptophan is absent (allowing transcription to proceed). The trp operon additionally uses attenuation to control expression of the operon, a second negative feedback control mechanism.
The trp operon is well-studied and is commonly used as an example of gene regulation in bacteria alongside the lac operon.
^Merino E, Jensen RA, Yanofsky C (April 2008). "Evolution of bacterial trp operons and their regulation". Current Opinion in Microbiology. 11 (2): 78–86. doi:10.1016/j.mib.2008.02.005. PMC 2387123. PMID 18374625.
inhibited by a chemical (tryptophan). This operon contains five structural genes: trp E, trp D, trp C, trp B, and trp A, which encodes tryptophan synthetase...
pathway in bacteria. There are 5 operons which are regulated by trpR: the trpEDCBA, trpR, AroH, AroL, and mtr operons. When the amino acid tryptophan is...
activate a repressor protein, which binds to the trpoperon. Binding of this repressor to the tryptophan operon prevents transcription of downstream DNA that...
the operon. At least 6 different amino acid operons are known to be regulated by this attenuation. The formation of the terminator requires the trp RNA-binding...
polymerase pausing and termination participates in the Bacillus subtilis trpoperon attenuation mechanism in vitro. Proc. Natl. Acad. Sci. USA. 99:11067-11072...
early in evolution the trpB2 gene was duplicated. One copy entered the trpoperon as trpB2i allowing for its expression with trpA. TrpB2i formed transient...
repressor (TrpR) is only able to bind to DNA and repress transcription of the trpoperon when its corepressor tryptophan is bound to it. TrpR in the absence...
extraneous factors can modify the termination behavior. Rho factor WebGeSTer Trpoperon Farnham, PJ; Platt, T (11 February 1981). "Rho-independent termination:...
Co-Evolution Predicts Known Physical Interactions in Bacterial Ribosomes and the TrpOperon". PLOS ONE. 11 (2): e0149166. arXiv:1512.05420. Bibcode:2016PLoSO..1149166F...
termed an aporepressor or inactive repressor. One type of aporepressor is the trp repressor, an important metabolic protein in bacteria. The above mechanism...
products of trpE and trpG. trpE encodes the first subunit, which binds to chorismate and moves the amino group from the donor to chorismate. trpG encodes...
(2004), "The different roles of tryptophan transfer RNA in regulating trpoperon expression in E. coli versus B. subtilis", Trends Genet., vol. 20, no...
anthranilate synthase are encoded by the trpE and trpD genes in E. coli, both of which appear in the trpoperon. In Enterobacteriaceae, this enzyme exists...
been shown to lower the operon expression, and which is already involved in the attenuation of the Trp, His and S10 operons. Naville, M; Gautheret, D...
Yanofsky, Charles (1975-02-15). "Interaction of the trp repressor and RNA polymerase with the trpoperon". Journal of Molecular Biology. 92 (1): 93–111. doi:10...
acids core peptide derived from a longer precursor, with unusual Trp-1 to Trp-3 and Trp-3 to Lys-5 (or Arg-5, in variant forms) crosslinks. The key enzyme...
evolution, and tend to encode proteins that interact or are part of the same operon. Thus, chromosomal proximity also called the gene neighbour method can be...
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