Mapping of gshA, a gene for the biosynthesis of glutathione in Eschericha coli K12

Apontoweil, P.; Berends, W.

doi:10.1007/bf00267676

Cited by 24 publications

(12 citation statements)

References 9 publications

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“…Transduction of the gshA20: :TnlOkm mutation into NK5991 or KL164 gave cotransduction frequencies (18% with srlD; 34% with naiB) in agreement with the known map position of the gshA gene near 58 min (4,5). Consistent with the gshA mutant genotype was the observation that JTG10 was exceptionally resistant to toxic agents thought to require thiols for their activation.…”

supporting

confidence: 78%

Glutathione in Escherichia coli is dispensable for resistance to H2O2 and gamma radiation

Greenberg¹,

Demple²

1986

J Bacteriol

141

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supporting

confidence: 78%

Glutathione in Escherichia coli is dispensable for resistance to H2O2 and gamma radiation

Greenberg¹,

Demple²

1986

J Bacteriol

141

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“…We showed that gshA mutants of S. enterica were thiamine auxotrophs, yet no nutritional requirement was reported for gshA mutants of E. coli (2). To confirm this apparent difference, a gshA mutant of E. coli was obtained from the E. coli Genetic Stock Center (JTG10) and the gshA insertion was transduced by phage P1 into E. coli K12.…”

Section: Resultsmentioning

confidence: 99%

Lesions in gshA (Encoding γ- l -Glutamyl- l -Cysteine Synthetase) Prevent Aerobic Synthesis of Thiamine in Salmonella enterica Serovar Typhimurium LT2

et al. 2000

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Thiamine pyrophosphate is an essential cofactor that is synthesized de novo in Salmonella enterica serovar Typhimurium and other bacteria. In addition to genes encoding enzymes in the biosynthetic pathway, mutations in other metabolic loci have been shown to prevent thiamine synthesis. The latter loci identify the integration of the thiamine biosynthetic pathway with other metabolic processes and can be uncovered when thiamine biosynthesis is challenged. Mutations in gshA, encoding ␥-L-glutamyl-L-cysteine synthetase, prevent the synthesis of glutathione, the major free thiol in the cell, and are shown here to result in a thiamine auxotrophy in some of the strains tested, including S. enterica LT2. Phenotypic characterization of the gshA mutants indicated they were similar enough to apbC and apbE mutants to warrant the definition of a class of mutants unified by (i) a requirement for both the hydroxymethyl pyrimidine (HMP) and thiazole (THZ) moiety of thiamine, (ii) the ability of L-tryosine to satisfy the THZ requirement, (iii) suppression of the thiamine requirement by anaerobic growth, and (iv) suppression by a second-site mutation at a single locus. Genetic data indicated that a defective ThiH generates the THZ requirement in these strains, and we suggest this defect is due to a reduced ability to repair a critical [Fe-S] cluster.Thiamine pyrophosphate (TPP) is an essential cofactor for several enzymes, including pyruvate dehydrogenase, transketolase, and acetolactate synthase, for which it functions as a carbon unit carrier and electron sink. TPP is composed of two independently synthesized moieties, 4-methyl-5-␤-hydroxyethyl-thiazole monophosphate (THZ-P) and 4-amino-5-hydroxymethyl-2-methylpyrimidine pyrophosphate (HMP-PP). Although several recent studies have increased our understanding of the synthesis of TPP in Escherichia coli and Salmonella enterica (5,31,39,46,51,52,53), many central issues have yet to be resolved. The current understanding of the substrates and enzymes in TPP synthesis are outlined in Fig. 1A (6,15,[20][21][22][23]43,54,55). Significantly, L-Tyr donates a single carbon and the nitrogen atom to the thiazole (THZ) ring.Of the five genes implicated in the synthesis of THZ-P in S. enterica and E. coli (5,49,51), the products of thiFSGI have been assigned functions based on in vitro activity assays (31,46,47). However, the order of the steps and the specific metabolites in this biosynthesis have not been rigorously defined. The precursor for the pyrimidine (HMP) moiety was shown to be the purine biosynthetic intermediate, aminoimidazole ribotide (AIR) (22). The steps involved in the conversion of AIR to HMP are unknown, and to date, mutations in only one gene, thiC, have resulted in an unconditional requirement for HMP or thiamine.Past work showed that mutations in several loci distinct from the thi genes could result in a thiamine auxotrophy. Characterization of several mutations that indirectly affected thiamine synthesis has increased our understanding of thiamine synthesis and its i...

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“…Surprisingly, some mutants of E. cofi deficient in glutathione biosynthesis do not grow abnormally, and at least one strain did not show increased sensitivity to X-rays (94). However, in other isolates, which accumulate significant y-glutamylcysteine, the bacteria were more sensitive to X-rays and thiol oxidizing chemicals (92).…”

Section: B Cellular Redox Buffersmentioning

confidence: 99%

Molecular and Cellular Aspects of Thiol–Disulfide Exchange

Gilbert

1990

Advances in Enzymology - And Related Areas of Molecular Biology

439

304

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Mapping of gshA, a gene for the biosynthesis of glutathione in Eschericha coli K12

Cited by 24 publications

References 9 publications

Glutathione in Escherichia coli is dispensable for resistance to H2O2 and gamma radiation

Glutathione in Escherichia coli is dispensable for resistance to H2O2 and gamma radiation

Lesions in gshA (Encoding γ- l -Glutamyl- l -Cysteine Synthetase) Prevent Aerobic Synthesis of Thiamine in Salmonella enterica Serovar Typhimurium LT2

Molecular and Cellular Aspects of Thiol–Disulfide Exchange

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