Escherichia coli tryptophan synthesis

Zalkin, H., Yanofsky C. and Squires, C. L. (1974) Regulated in vitro synthesis of Escherichia coli tryptophan operon messenger ribonucleic acid and enzymes. J. Biol. Chem. 249, 465. 

The trp repressor controls the operon for the synthesis of L-tryptophan in Escherichia coli by a simple negative feedback loop. In the absence of L-tryptophan, the repressor is inactive, the operon is switched on and the enzymes which synthesize L-tryptophan are produced. As the concentration of L-tryptophan increases, it binds to the repressor and converts it to an active form so that it can bind to the operator region and switch off the gene. 

The thousands of enzyme-catalyzed chemical reactions in living cells are organized into a series of biochemical (or metabolic) pathways. Each pathway consists of a sequence of catalytic steps. The product of the first reaction becomes the substrate of the next and so on. The number of reactions varies from one pathway to another. For example, animals form glutamine from a-ketoglutarate in a pathway that has two sequential steps, whereas the synthesis of tryptophan by Escherichia coli requires 13 steps. Frequently, biochemical pathways have branch points. For example, chorismate, a metabolic intermediate in tryptophan biosynthesis, is also a precursor of phenylalanine and tyrosine. 

Sen, A.K. W. Liu. 1990. Dynamic analysis of genetic control and regulation of amino acid synthesis The tryptophan operon in Escherichia coli. Biotechnol. Bioeng. 35 185-94. 

C2H5OH). C. is a broad-spectrum antibiotic isolated from Actinoplanes jinanensis. In China C. is used to treat Escherichia coli infections, the activity seems to be based on inhibition of tryptophan biosynthesis. Lit. Chem. Pharm. Bull. 42, 271 -276 (1994) (synthesis) J. Chem. Soc., Perkin Trans. 1 1992, 323 ff. Sci. Sinica Engl. Ed. 20, 106 (1977) Tetrahedron Asymmetry 8,2295 (1997) (synthesis) Tetrahedron Lett. 34,489 (1993) (synthesis) 38, 1805 (1997) [synthesis ( )-C.V- [CAS63339-68-4]... 

The properties of Escherichia coli cells entrapped in /c-carrageenan and then glutaraldehyde-cross-linked have been investigated and used for the production of L-aspartic acid. L-Tryptophan has been synthesized by E. coli cells entrapped in polyacrylamide. A correction to a previously published paper on the synthesis of L-tryptophan by immobilized E. coli cells has been noted. ... 

Gu P, KangJ.Yang F, Wang Q, Liang Q, Qi Q.The improved 1-tryptophan production in recombinant Escherichia coli by expressing the polyhydroxybutyrate synthesis pathway. Appl Microbiol Biotechnol 2013 97 4121-7. 

Yanofsky, C. and Lennox, E. S. (1959) Transduction and recombination study of linkage relationships among the genes controlling tryptophan synthesis in Escherichia coli. Virology, 8,425-447. 

The evidence that (- )-shikimic acid plays a central role in aromatic biosynthesis was obtained by Davis with a variety of nutritionally deficient mutants of Escherichia coli. In one group of mutants with a multiple requirement for L-tyrosine, L-phenylalanine, L-tryptophan and p-aminobenzoic acid and a partial requirement for p-hydroxybenzoic acid, (—)-shikimic acid substituted for all the aromatic compounds. The quintuple requirement for aromatic compounds which these mutants displayed arises from the fact that, besides furnishing a metabolic route to the three aromatic a-amino acids, the shikimate pathway also provides in micro-organisms a means of synthesis of other essential metabolites, and in particular, the various isoprenoid quinones involved in electron transport and the folic acid group of co-enzymes. The biosynthesis of both of these groups of compounds is discussed below. In addition the biosynthesis of a range of structurally diverse metabolites, which are derived from intermediates and occasionally end-products of the pathway, is outlined. These metabolites are restricted to certain types of organism and their function, if any, is in the majority of cases obscure. 

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