User:Dudleydoodog/Trp operon

Existing Article: Trp Operon
The bolded sentences are my own.

Genes
Trp operon contains five structural genes. Their roles are


 * Trp operon organization across three different bacterial species.png : Anthranilate synthase produces anthranilate.
 * TrpD : Cooperates with TrpE.
 * TrpC : Phosphoribosylanthranilate isomerase domain first turns N-(5-phospho-β-D-ribosyl)anthranilate into 1-(2-carboxyphenylamino)-1-deoxy-D-ribulose 5-phosphate. The Indole-3-glycerol-phosphate synthase on the same protein then turns the product into (1S,2R)-1-C-(indol-3-yl)glycerol 3-phosphate.
 * TrpA, TrpB : two subunits of tryptophan synthetase. Combines TrpC's product with serine to produce tryptophan.

Regulation of trp operon in Bacillus subtilis
Trp operon genes are arranged in the same order in E. coli and Bacillus subtilis. 'The arrangement of the trp operon in E. coli and Bacillus subtilis'' differs. There are 5 structural genes in E. coli that are found under a single transcriptional unit. In Bacillus subtilis, there are 6 structural genes that are situated within a supraoperon. Three of these genes are found upstream while the other three genes are found downstream of the trp operon. There is a 7th gene in Bacillus subtilis' s operon called trpG or pabA which is responsible for protein synthesis of tryptophan and folate.''' Regulation of trp operons in both organisms depends on the amount of trp present in the cell. However, the primary regulation of tryptophan biosynthesis in B. subtilis is via attenuation, rather than repression, of transcription. In B. subtilis, tryptophan binds to the eleven-subunit tryptophan-activated RNA-binding attenuation protein (TRAP), which activates TRAP's ability to bind to the trp leader RNA. Binding of trp-activated TRAP to leader RNA results in the formation of a terminator structure that causes transcription termination. '''In addition, the activated TRAP inhibits the initiation of translation of trpP, trpE, trpG and ycbK genes. The gene trpP plays a role in trp transportation, while the gene trpG is utilized in the folate operon, and the gene ycbK is involved in synthesis of an efflux protein. The activated TRAP protein is regulated by an anti-TRAP protein and AT synthesis. AT can inactive TRAP to lower the transcription of tryptophan.'''