Disease relevance of tnaA

• When a tnaA-disrupted E. coli strain expressing the altered cysE gene was transformed with a plasmid carrying the bcr gene, the transformant exhibited more L-cysteine production than cells carrying the vector only [1].
• The structure shares the same fold with and has similar quaternary structure to Proteus vulgaris tryptophanase and tyrosine-phenol lyase, but is found in a closed conformation when compared with these two enzymes [2].

High impact information on tnaA

• Apo- and holoenzyme are inactivated at the same rate, and inactivation of both is correlated with modification of 2 arginine residues/tryptophanase monomer [3].
• Tryptophanase from Escherichia coli B/1t7-A is inactivated by the arginine-specific reagent, phenylglyoxal, in potassium phosphate buffer at pH 7.8 AND 25 degrees [3].
• We have identified tryptophanase (which catabolizes tryptophan to pyruvate and indole) as an Rcd binding protein [4].
• Furthermore, the stabilization of multicopy plasmids by Rcd is shown to be tryptophanase dependent, and a tryptophanase-deficient strain is resistant to growth inhibition by Rcd overexpression [4].
• Kinetics of tryptophanase inactivation/activation by sudden removal/addition of potassium ions with the aid of a crown ether or cryptand [5].

Chemical compound and disease context of tnaA

• Essential arginine residues in tryptophanase from Escherichia coli [3].
• From strains of Escherichia coli that carry deletions of the trp region, five different mutants were isolated that were capable of synthesizing tryptophanase at unusually high rates in conditions of severe catabolite repression [6].
• Pyridoxal 5'-phosphate (PLP) dependent tryptophanase has been isolated from Escherichia coli and its crystal structure has been determined [2].
• Immunochemical studies on the evolution of tryptophanase and the two subunits of tryptophan synthetase of Escherichia coli K 12 [7].
• To identify proteins over- or under-expressed in response to E. coli biofilm formation and indole signalling, we compared the proteomes of the E. coli S17-1 wild-type and 3714 (S17-1 tnaA::Tn5) tryptophanase-negative mutant cells (which don't produce indole) grown as suspensions or biofilms in the presence or absence of exogenous indole [8].

Biological context of tnaA

• Portions of the genomes (including the tnaA and thyA genes, the trp operon, and one other unassigned segment) appear to have evolved in concert with the genome as a whole [9].
• The tryptophanase structure, solved in its apo form, does not have covalent PLP bound in the active site, but two sulfate ions [2].

Associations of tnaA with chemical compounds

• Rcd increases the affinity of tryptophanase for its substrate tryptophan which causes increased indole production by cells in low-density cultures [4].
• Nalidixic acid (Nal), a drug which affects deoxyribonucleic acid gyrase activity, inhibits the expression of catabolite-sensitive genes: the three maltose operons, the lactose and galactose operons, and the tryptophanase gene [10].
• Four of the first five N-terminal residues are homologeous with tryptophanase, another pyridoxal-phosphate (P-Pxy) enzyme that catalyzes alpha,beta-elimination reactions [11].

Other interactions of tnaA

• When inducing simultaneously beta-galactosidase and tryptophanase in a batch culture either the synthesis of tryptophanase or of both enzymes is decreased due to an insufficient cAMP concentration [12].

References