Regulation of glutamine synthetase, aspartokinase, and total protein turnover in Klebsiella aerogenes

Fulks, Richard M.; Stadtman, Earl R.

doi:10.1016/0304-4165(85)90142-4

Cited by 30 publications

(8 citation statements)

References 32 publications

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“…The oxidative modification of His-269 to Asn and Arg-344 to Gln induces the loss of activity of GS followed by increased susceptibility to proteolytic degradation (26). This mechanism is thought to be one of the regulation systems of the concentration of GS protein in the cell (34). As in GS, site-directed mutagenesis of the corresponding two amino acids of PuuA decreased its enzyme activity, and mutated PuuAs were rapidly inactivated.…”

Section: Discussionmentioning

confidence: 99%

γ-Glutamylputrescine Synthetase in the Putrescine Utilization Pathway of Escherichia coli K-12

Kurihara

Oda

Tsuboi

et al. 2008

Journal of Biological Chemistry

110

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Glutamate-putrescine ligase (␥-glutamylputrescine synthetase, PuuA, EC 6.3.1.11) catalyzes the ␥-glutamylation of putrescine, the first step in a novel putrescine utilization pathway involving ␥-glutamylated intermediates, the Puu pathway, in Escherichia coli. In this report, the character and physiological importance of PuuA are described. Purified non-tagged PuuA catalyzed the ATP-dependent ␥-glutamylation of putrescine. The K m values for glutamate, ATP, and putrescine are 2.07, 2.35, and 44.6 mM, respectively. There are two putrescine utilization pathways in E. coli: the Puu pathway and the pathway without ␥-glutamylation. Gene deletion experiments of puuA, however, indicated that the Puu pathway was more critical in utilizing putrescine as a sole carbon or nitrogen source. The transcription of puuA was induced by putrescine and in a puuR-deleted strain. The amino acid sequences of PuuA and glutamine synthetase (GS) show high similarity. The molecular weights of the monomers of the two enzymes are quite similar, and PuuA exists as a dodecamer as does GS. Moreover the two amino acid residues of E. coli GS that are important for the metal-catalyzed oxidation of the enzyme molecule involved in protein turnover are conserved in PuuA, and it was experimentally shown that the corresponding amino acid residues in PuuA were involved in the metal-catalyzed oxidation similarly to GS. It is suggested that the intracellular concentration of putrescine is optimized by PuuA transcriptionally and posttranslationally and that excess putrescine is converted to a nutrient source by the Puu pathway.

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Section: Discussionmentioning

confidence: 99%

γ-Glutamylputrescine Synthetase in the Putrescine Utilization Pathway of Escherichia coli K-12

Kurihara

Oda

Tsuboi

et al. 2008

Journal of Biological Chemistry

110

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“…Early studies by Turnbough and Switzer [37,38] examined the idea of metal-ion-catalysed inactivation of enzymes as a trigger for proteolytic removal. Two fascinating papers [52,203] concern protein catabolism in differentiating Klebsiella aerogenes and K. pneumoniae respectively. The argument is put forward [203] that inactivation of aspartokinases III (lysine-sensitive) and I precede and lead to their enzymic proteolysis when K. aerogenes is incubated in a nitrogen-lacking medium.…”

Section: Oxidized Proteins In the Control Of Cell Growth And Differenmentioning

confidence: 99%

“…Two fascinating papers [52,203] concern protein catabolism in differentiating Klebsiella aerogenes and K. pneumoniae respectively. The argument is put forward [203] that inactivation of aspartokinases III (lysine-sensitive) and I precede and lead to their enzymic proteolysis when K. aerogenes is incubated in a nitrogen-lacking medium. However, a detailed analysis of these data and earlier immunological studies [39] showed only that the two processes occur very close together.…”

Section: Oxidized Proteins In the Control Of Cell Growth And Differenmentioning

confidence: 99%

Biochemistry and pathology of radical-mediated protein oxidation

Dean

Stocker

et al. 1997

Biochemical Journal

1,548

982

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Radical-mediated damage to proteins may be initiated by electron leakage, metal-ion-dependent reactions and autoxidation of lipids and sugars. The consequent protein oxidation is O2-dependent, and involves several propagating radicals, notably alkoxyl radicals. Its products include several categories of reactive species, and a range of stable products whose chemistry is currently being elucidated. Among the reactive products, protein hydroperoxides can generate further radical fluxes on reaction with transition-metal ions; protein-bound reductants (notably dopa) can reduce transition-metal ions and thereby facilitate their reaction with hydroperoxides; and aldehydes may participate in Schiff-base formation and other reactions. Cells can detoxify some of the reactive species, e.g. by reducing protein hydroperoxides to unreactive hydroxides. Oxidized proteins are often functionally inactive and their unfolding is associated with enhanced susceptibility to proteinases. Thus cells can generally remove oxidized proteins by proteolysis. However, certain oxidized proteins are poorly handled by cells, and together with possible alterations in the rate of production of oxidized proteins, this may contribute to the observed accumulation and damaging actions of oxidized proteins during aging and in pathologies such as diabetes, atherosclerosis and neurodegenerative diseases. Protein oxidation may also sometimes play controlling roles in cellular remodelling and cell growth. Proteins are also key targets in defensive cytolysis and in inflammatory self-damage. The possibility of selective protection against protein oxidation (antioxidation) is raised.

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“…, 1993) and by reversible covalent adenylation (Stadtman, 1990), and the structural gene for GS, glnA , is subject to transcriptional regulation (Magasanik, 1989). Although normally stable, GS is turned over when cells are starved of nitrogen (Fulks and Stadtman, 1985; Stadtman and Berlett, 1997), indicating that the intracellular level of GS in bacterial cells is also regulated by proteolysis. Glutamine synthetase in Saccharomyces cerevisiae (yeast) is also under strong transcriptional regulation responding to glutamine–glutamate shift and purine deprivation (Minehart and Magasanik, 1992).…”

Section: Introductionmentioning

confidence: 99%

The 3′ untranslated region of a soybean cytosolic glutamine synthetase (GS₁) affects transcript stability and protein accumulation in transgenic alfalfa

et al. 2006

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SummaryHigher plants assimilate nitrogen in the form of ammonia through the concerted activity of glutamine synthetase (GS) and glutamate synthase (GOGAT). The GS enzyme is either located in the cytoplasm (GS 1 ) or in the chloroplast (GS 2 ). Glutamine synthetase 1 is regulated in different plants at the transcriptional level and there are some reports of regulation at the level of protein stability. Here we present data that clearly establish that GS 1 in plants is also regulated at the level of transcript turnover and at the translational level. Using a Glycine max (soybean) GS 1 transgene, with and without its 3¢ untranslated region (UTR), driven by the constitutive CaMV 35S promoter in Medicago sativa (alfalfa) and Nicotiana tabacum (tobacco), we show that the 3¢ UTR plays a major role in both transcript turnover and translation repression in both the leaves and the nodules. Our data suggest that the 3¢ UTR mediated turnover of the transcript is regulated by a nitrogen metabolite or carbon/nitrogen ratios. We also show that the 3¢ UTR of the gene for the soybean GS 1 confers post-transcriptional regulation on a reporter gene. Our dissection of post-transcriptional and translational levels of regulation of GS in plants shows that the situation in plants strongly resembles that in other organisms where GS is regulated at almost all levels. Multistep regulation of GS shows the high priority given by organisms to regulating and ensuring optimal control of nitrogen substrates and preventing overproduction of glutamine and drainage of the glutamate pool.

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Regulation of glutamine synthetase, aspartokinase, and total protein turnover in Klebsiella aerogenes

Cited by 30 publications

References 32 publications

γ-Glutamylputrescine Synthetase in the Putrescine Utilization Pathway of Escherichia coli K-12

γ-Glutamylputrescine Synthetase in the Putrescine Utilization Pathway of Escherichia coli K-12

Biochemistry and pathology of radical-mediated protein oxidation

The 3′ untranslated region of a soybean cytosolic glutamine synthetase (GS₁) affects transcript stability and protein accumulation in transgenic alfalfa

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Regulation of glutamine synthetase, aspartokinase, and total protein turnover in Klebsiella aerogenes

Cited by 30 publications

References 32 publications

γ-Glutamylputrescine Synthetase in the Putrescine Utilization Pathway of Escherichia coli K-12

γ-Glutamylputrescine Synthetase in the Putrescine Utilization Pathway of Escherichia coli K-12

Biochemistry and pathology of radical-mediated protein oxidation

The 3′ untranslated region of a soybean cytosolic glutamine synthetase (GS1) affects transcript stability and protein accumulation in transgenic alfalfa

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The 3′ untranslated region of a soybean cytosolic glutamine synthetase (GS₁) affects transcript stability and protein accumulation in transgenic alfalfa