This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
|Superclasses:||Biosynthesis → Amino Acids Biosynthesis → Proteinogenic Amino Acids Biosynthesis → L-typtophan Biosynthesis|
Some taxa known to possess this pathway include : Arabidopsis thaliana col [Li96a], Bacillus subtilis, Escherichia coli K-12 substr. MG1655, Sulfolobus solfataricus, Thermococcus kodakarensis, Thermotoga maritima
Tryptophan biosynthesis in microbes involves five enzymes, encoded by 7 genes. The genes (trpA,B,C,D,E,F) are usually arranged in a single cluster [Crawford89], and form an operon whose transcription is negatively regulated by tryptophan [Yanofsky81]. Additional regulation mechanisms exist at the translational and post-translational levels, presumably because tryptophan synthesis is very expensive (78 mol ATP for each mol of tryptophan produced). In addition, hyperthermophilic organisms usually have an additional gene, trpB2, which is located outside of the tryptophan operon. This gene encodes an additional enzyme which is similar to a subunit of tryptophan synthase.
The two last steps in this pathway are catalyzed by a single enzyme, tryptophan synthase, which is composed of two α and two β subunits (E.C. reaction 126.96.36.199). However, it has been shown that each of the subunits is responsible for catalyzing an individual step, and is able to catalyze that step on its own. Thus, the activity of tryptophan synthase was divided into two individual steps in the pathway, each catalyzed by the corresponding subunit.
Adachi74: Adachi O, Kohn LD, Miles EW (1974). "Crystalline alpha2 beta2 complexes of tryptophan synthetase of Escherichia coli. A comparison between the native complex and the reconstituted complex." J Biol Chem 249(24);7756-63. PMID: 4609974
Adams14: Adams NE, Thiaville JJ, Proestos J, Juarez-Vazquez AL, McCoy AJ, Barona-Gomez F, Iwata-Reuyl D, de Crecy-Lagard V, Maurelli AT (2014). "Promiscuous and adaptable enzymes fill "holes" in the tetrahydrofolate pathway in Chlamydia species." MBio 5(4). PMID: 25006229
Akanuma05: Akanuma S, Miyagawa H, Kitamura K, Yamagishi A (2005). "A detailed unfolding pathway of a (beta/alpha)8-barrel protein as studied by molecular dynamics simulations." Proteins 58(3);538-46. PMID: 15614829
Andreotti94: Andreotti G, Tutino ML, Sannia G, Marino G, Cubellis MV (1994). "Indole-3-glycerol-phosphate synthase from Sulfolobus solfataricus as a model for studying thermostable TIM-barrel enzymes." Biochim Biophys Acta 1208(2);310-5. PMID: 7947963
Bartholmes76: Bartholmes P, Kirschner K, Gschwind HP (1976). "Cooperative and noncooperative binding of pyridoxal 5'-phosphate to tryptophan synthase from Escherichia coli." Biochemistry 15(21);4712-7. PMID: 788781
Beasty86: Beasty AM, Hurle MR, Manz JT, Stackhouse T, Onuffer JJ, Matthews CR (1986). "Effects of the phenylalanine-22----leucine, glutamic acid-49----methionine, glycine-234----aspartic acid, and glycine-234----lysine mutations on the folding and stability of the alpha subunit of tryptophan synthase from Escherichia coli." Biochemistry 25(10);2965-74. PMID: 2872918
Christie80: Christie GE, Platt T (1980). "Gene structure in the tryptophan operon of Escherichia coli. Nucleotide sequence of trpC and the flanking intercistronic regions." J Mol Biol 1980;142(4);519-30. PMID: 7007653
Creighton70: Creighton TE (1970). "N-(5'-phosphoribosyl)anthranilate isomerase-indol-3-ylglycerol phosphate synthetase of tryptophan biosynthesis. Relationship between the two activities of the enzyme from Escherichia coli." Biochem J 120(4);699-707. PMID: 4924490
Darimont98: Darimont B, Stehlin C, Szadkowski H, Kirschner K (1998). "Mutational analysis of the active site of indoleglycerol phosphate synthase from Escherichia coli." Protein Sci 7(5);1221-32. PMID: 9605328
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
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