Disease relevance of L-5-Methyltryptophan

• Differential sensitivity of the transformed E. coli strains toward 5-methyltryptophan, a false-feedback inhibitor of AS, was demonstrated [1].
• The trpD gene from tryptophan-hyperproducing Corynebacterium glutamicum ATCC 21850 was isolated on the basis of its ability to confer resistance to 5-methyltryptophan on wild-type C. glutamicum AS019 [2].
• The systems include forward mutations leading to resistance against 5-methyltryptophan (MTR) and from galR-s18 to gal-+ in Escherichia coli 343/113, back mutations from arg56 to arg-+ in Escherichia coli 343/113 and back mutations from hisG46 to his-+ in Salmonella typhimurium TA1535 [3].

High impact information on L-5-Methyltryptophan

• Placement of unrelated promoters adjacent to the direct repeat sequences restored 5-methyltryptophan resistance [4].
• No significant differences in the doubling times of TRP3 or TRP3pr yeast transformants were observed during growth at 25 degrees C, 30 degrees C or 37 degrees C, or in the presence of sublethal concentrations of the analogue, 5-methyltryptophan [5].
• Deuterium decoupled, triple resonance NMR spectroscopy was used to analyze complexes of 2H, 15N, 13C labelled intact and (des2-7) trp repressor (delta 2-7 trpR) from E. coli bound in tandem to an idealized 22 basepair trp operator DNA fragment and the corepressor 5-methyltryptophan [6].
• 73, a derivative of a previously isolated rice mutant (TR-1) that is resistant to 5-methyltryptophan [7].
• Mutations in the trpD gene of Corynebacterium glutamicum confer 5-methyltryptophan resistance by encoding a feedback-resistant anthranilate phosphoribosyltransferase [2].

Biological context of L-5-Methyltryptophan

• Removal of either the trp promoter or the adjacent direct repeat sequences abolished the 5-methyltryptophan-resistance phenotype [4].
• The mutant plasmid that did not respond to 5-methyltryptophan either produces an exceedingly low basal level of penicillinase or does not produce active enzyme [8].
• There are, however, some differences in chemical shifts and NOE for 5-methyltryptophan, which indicate that there are significant differences between the two corepressors L-tryptophan and 5-methyltryptophan in the orientation of the indole ring within the binding site [9].
• A sequence sufficient to mediate resistance to 5-methyltryptophan in E. coli was mapped to a 582-bp sequence located immediately upstream of the C. glutamicum trp operon [10].

Anatomical context of L-5-Methyltryptophan

• To increase the specific free amino acid content in the japonica rice (Oryza sativa L.) cultivar Donganbyeo, mutant cell lines resistant to growth inhibition by 5-methyltryptophan (5MT) were selected from embryo-cultured callus irradiated with 50 Gy gamma-rays [11].

Associations of L-5-Methyltryptophan with other chemical compounds

• It appears that an approximately 120-base-pair region comprising not only the trp promoter but also adjacent direct repeat sequences is necessary to confer 5-methyltryptophan resistance [4].
• Further analysis demonstrated that the trpD gene product from ATCC 21850, anthranilate phosphoribosyltransferase, was more resistant to feedback inhibition by either tryptophan or 5-methyltryptophan than its wild-type counterpart [2].

Gene context of L-5-Methyltryptophan

• Cells with lesions in mtr display a phenotype of 5-methyltryptophan resistance [12].
• Among a group of 5-methyltryptophan (MT) resistant derivatives of trpA mutants we encountered several with a novel phenotype: they actually grew better in the presence of MT than in its absence [13].
• 5-methyltryptophan seems to induce penicillinase synthesis in wild-type plasmids by becoming incorporated into the repressor and thereby inactivating the operator binding function of the penicillinase repressor [8].

References