Disease relevance of trpA

• The suppressor allows readthrough of UGA mutations at two positions in trpA and at two sites in bacteriophage T4 [1].
• A molecular characterization of spontaneous frameshift mutagenesis within the trpA gene of Escherichia coli [2].

High impact information on trpA

• The suppressor also does not allow mistranslation of the UGA-related trpA missense mutations UGG at positions 211 and 234, AGA at 211 and 234, CGA at 211, or UGU and UGC at 234 [1].
• The urea-induced unfolding of the Escherichia coli tryptophan synthase alpha-subunit is examined via fluorescence measurements with tryptophan-containing alpha-subunit mutants, constructed by in vitro mutagenesis [3].
• Evidence that glutamic acid 49 of tryptophan synthase alpha subunit is a catalytic residue. Inactive mutant proteins substituted at position 49 bind ligands and transmit ligand-dependent to the beta subunit [4].
• An NH2-terminal 239 amino acid segment of yeast tryptophan synthase is homologous with E. coli tryptophan synthase alpha subunit, while a distal 389 amino acid residue segment is homologous to the E. coli tryptophan synthase beta chain [5].
• Unfolding-refolding kinetics of the tryptophan synthase alpha subunit by CD and fluorescence measurements [6].

Chemical compound and disease context of trpA

• To elucidate the folding mechanism of the tryptophan synthase alpha subunit from Escherichia coli, the kinetics of the unfolding-refolding were studied by peptidyl circular dichroism (CD) and aromatic fluorescence measurement at pH 7 and 25 degrees C. The reactions were induced by concentration jumps of guanidine hydrochloride (GuHCl) [6].
• Conformational changes in the alpha-subunit coupled to binding of the beta 2-subunit of tryptophan synthase from Escherichia coli: crystal structure of the tryptophan synthase alpha-subunit alone [7].
• Photoaffinity labeling of the indole sites on the Escherichia coli tryptophan synthase alpha-subunit [8].
• The fluorescence of tyrosine has been used to monitor a folding process of tryptophan synthase alpha-subunit from Escherichia coli, because this protein has 7 tyrosines, but not tryptophan [9].
• Comparison of denaturation by guanidine hydrochloride of the wild type tryptophan synthase alpha-subunit of Escherichia coli and two mutant protein (Glu 49 replaced by Met or Gln) [10].

Biological context of trpA

• The mutagenized fragments were subcloned into the plasmid vector and used to transform to ampicillin resistance (Ampr) a recipient strain containing a UGA mutation in trpA [11].
• There was a dense pattern of reversion sites within the trpA DNA region where reversion events could occur, suggesting that, in general, most DNA sequences are capable of undergoing spontaneous mutational events during replication that can lead to small deletions and insertions [2].
• These studies also revealed an unpredicted flexibility in the primary amino acid sequence of the trpA product, the alpha subunit of tryptophan synthase [2].
• The molecular characterization of the mutation that corrected the Eut- phenotype caused by allele Delta903 showed that the new mutation was a deletion of two nucleotides at the tonB-trpA fusion site [12].
• In order to elucidate the effect of single amino acid substitutions on the conformation of the tryptophan synthase alpha-subunit from Escherichia coli in solution, 1H NMR spectra of the wild-type and mutant proteins were measured at various pHs [13].

Associations of trpA with chemical compounds

• Equilibrium and kinetic analyses of unfolding and refolding for the conserved proline mutants of tryptophan synthase alpha subunit [14].
• Role of conserved proline residues in stabilizing tryptophan synthase alpha subunit: analysis by mutants with alanine or glycine [15].
• The tryptophan synthase alpha subunit catalyzes the conversion of indole-3-glycerolphosphate to indole, the penultimate reaction in the biosynthesis of the essential amino acid tryptophan [16].
• Assignment of tyrosine resonances in the 1H-NMR spectrum of tryptophan synthase alpha-subunit. Monitoring conformational changes due to substitutions at position 49 [17].
• Guanidine hydrochloride-induced denaturation and thermal denaturation of three kinds of tryptophan synthase alpha subunit have been compared by circular dichroism measurements [18].

Analytical, diagnostic and therapeutic context of trpA

• To further characterize the intermediate state in the denaturation of tryptophan synthase alpha subunit from Escherichia coli, we have carried out differential scanning calorimetry in various concentrations of urea near pH 8 [19].

References