Disease relevance of trpD

• The Thermotoga maritima trp operon is arranged with trpE forming an overlapping transcript with a second protein consisting of a fusion of anthranilate synthase component II (trpG) and anthranilate phosphoribosyltransferse (trpD) [1].
• At the 3'-end of the cro'-cat'-'trpE fused cistron there is a region for efficient translation reinitiation: a Shine-Dalgarno sequence of the E. coli trpD gene and the overlapping stop and start codons (TGATG) [2].
• Cysteine 84 was replaced by glycine in Serratia marcescens anthranilate synthase Component II using site-directed mutagenesis of cloned trpG [3].
• The most highly conserved region of the yeast and E. coli enzymes includes a cysteine residue previously found to be at the active site of Pseudomonas putida anthranilate synthase Component II (Kawamura, M., Keim, P.S., Goto, Y., Zalkin, H., and Heinrikson, R.L. (1978) J. Biol. Chem. 253, 4659-4668) [4].

High impact information on trpD

• Conserved amino acid residues likely to be essential for glutamine-dependent activity were identified by alignment of the glutamine amide transfer domains in four different enzymes: anthranilate synthase component II (AS II), p-aminobenzoate synthase component II, GMP synthetase, and carbamoyl-P synthetase [5].
• The mutation provides further evidence for the role of active site cysteine 84 in the glutamine amide transfer function of anthranilate synthase Component II [3].
• Amino acid sequence comparison with 19 trpE, 18 trpG and 14 trpD genes from other organisms suggest that the Thermotoga trp genes resemble corresponding genes from other thermophiles more closely than expected [1].
• In E. coli minicells, the plasmid insert directed the synthesis of polypeptides of 44,000, 33,000, and 20,000 daltons, molecular masses that are consistent with the reported molecular masses of phosphoribosylanthranilate transferase, indoleglycerol-phosphate synthase, and anthranilate-synthase component II, respectively [6].
• The trpD gene consists of 1593 nucleotides encoding 531 amino acids, and possesses an internal promoter (p2) located within a region from about 1400 to 1441 of the nucleotide sequence [7].

Chemical compound and disease context of trpD

• The vectors contain the Escherichia coli tryptophan promoter, the trpE gene, and about 15% of the trpD gene [8].

Biological context of trpD

• Southern analysis revealed that the integration had occurred through a single-crossover homologous recombination between the trpD regions of the host genome and the plasmid [9].
• The operon appears to lack the internal promoter within trpD that is common in terrestrial enteric species [10].
• Two of these cosmids also complemented trpD and carried an additional 4.2 kb HindIII fragment [11].
• The trpD and trpC genes each have three highly conserved 'Crawford' consensus sequences and are part of an operon with three open reading frames (ORFs) [12].

Associations of trpD with chemical compounds

• The cloned mouse gene confers trimethoprim resistance on B. subtilis and the cloned trp fragment complements mutations in the B subtilis trpD, C and F genes Expression of both cloned fragments is dependent on a promoter present in the vector plasmid [13].
• The chromosomal trp+ genes were transferred with frequencies of 10(-7) to 10(-6) only to one trpB and 2 trpD female parents, which have a point mutation in the 2nd and fourth structural genes, respectively, of the tryptophan operon [14].

References