Background: Microorganisms and plants are able to produce tryptophan. Enzymes catalysing the last seven steps of tryptophan biosynthesis are encoded in the canonical trp operon. Among the trp genes are most frequently trpA and trpB, which code for the alpha and beta subunit of tryptophan synthase. In several prokaryotic genomes, two variants of trpB (named trpB1 or trpB2) occur in different com...

Tryptophan synthase catalyzes the last two steps in the biosynthesis of the amino acid tryptophan. The enzyme is an complex in mesophilic microorganisms. The -subunit (TrpA) catalyzes the cleavage of indoleglycerol phosphate to glyceraldehyde 3-phosphate and indole, which is channeled to the active site of the associated -subunit (TrpB1), where it reacts with serine to yield tryptophan. The Trp...

Tryptophan synthase (TRPS), with linearly arrayed subunits alphabetabetaalpha, catalyzes the last two reactions in the biosynthesis of L-tryptophan. The two reactions take place in the respective alpha- and beta-subunits of the enzyme, and the intermediate product, indole, is transferred from the alpha- to the beta-site through a 25 A long hydrophobic tunnel. The occurrence of a unique ligand-m...

The genes for the large and small subunits of anthranilate synthase (trpE and trpG, respectively) have been cloned from Pseudomonas aeruginosa PAC174 into E. coli by R-prime formation with the broad-host-range plasmid R68.44. Sequential subcloning into plasmid vectors reduced the active Pseudomonas DNA fragment to a length of 3.1 kb. We obtained evidence that this region contains the promoter f...

The activity of the first enzyme of the shikimate pathway, 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase, is demonstrated in extracts of Daucus carota cells grown in suspension culture. Maximum specific enzyme activity is found midway through the logarithmic growth of the culture; cells in lag and stationary phases of growth have lower enzyme levels. The enzyme is activated by tyrosine a...

Two closely related subgroups of group I pseudomonads, which differ from one another in the overall enzymatic makeup of aromatic amino acid biosynthesis, possess in common the recently characterized major (tyrosine-sensitive) and minor (tryptophan-sensitive) isozymes of 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase of Pseudomonas aeruginosa (17). Since these characterizations were made f...

Anthranilate synthase [chorismate pyruvatelyase (amino-accepting), E.C.4.1.3.27] catalyzes the formation of anthranilate (o-aminobenzoate) and pyruvic acid from chorismate and glutamine. A mutant form of the enzyme from Salmonella typhimurium accumulates a compound that we had isolated and identified as trans-6-amino-5-[(1-carboxyethenyl)-oxy]-1,3- cyclohexadiene-1-carboxylic acid, commonly cal...

Tryptophan and its derivatives are important natural products and have many biochemical and synthetic applications. However, the more elaborate these derivatives are, the more complex the synthesis becomes. In this chapter, we summarize the development of an engineered enzymatic platform for synthesis of diverse tryptophan analogs. This endeavor utilizes the tryptophan synthase (TrpS) enzyme, a...