Tryptophan repressor

Tryptophan repressor

Tryptophan repressor is a transcription factor involved in controlling amino acid metabolism. It has been best studies in "Escherichia coli", where it is a dimeric protein that regulates transcription of the 5 genes in the tryptophan operon. [cite journal |author=Santillan M, Mackey MC |title=Dynamic regulation of the tryptophan operon: a modeling study and comparison with experimental data |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=98 |issue=4 |pages=1364–9 |year=2001 |pmid=11171956 |url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=11171956 |doi=10.1073/pnas.98.4.1364] When the amino acid tryptophan is plentiful in the cell, it binds to the protein, which causes a conformational change in the protein. [cite journal |author=Zhang RG, Joachimiak A, Lawson CL, Schevitz RW, Otwinowski Z, Sigler PB |title=The crystal structure of trp aporepressor at 1.8 A shows how binding tryptophan enhances DNA affinity |journal=Nature |volume=327 |issue=6123 |pages=591–7 |year=1987 |pmid=3600756 |doi=10.1038/327591a0] The repressor complex then binds to its operator sequence in the 5 genes it regulates, shutting off the genes. [cite journal |author=Jeeves M, Evans PD, Parslow RA, Jaseja M, Hyde EI |title=Studies of the Escherichia coli Trp repressor binding to its five operators and to variant operator sequences |journal=Eur. J. Biochem. |volume=265 |issue=3 |pages=919–28 |year=1999 |pmid=10518785 |doi=10.1046/j.1432-1327.1999.00792.x] [cite journal |author=Arvidson DN, Arvidson CG, Lawson CL, Miner J, Adams C, Youderian P |title=The tryptophan repressor sequence is highly conserved among the Enterobacteriaceae |journal=Nucleic Acids Res. |volume=22 |issue=10 |pages=1821–9 |year=1994 |pmid=8208606 |url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=8208606 |doi=10.1093/nar/22.10.1821]

One of these genes, trpR, codes for the production of tryptophan itself. Another codes for the tryptophan repressor protein. These are forms of feedback regulation.

ee also

* "trp repressor"

References


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