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. 1981 Feb;1(2):158–164. doi: 10.1128/mcb.1.2.158

Glutamate synthase levels in Neurospora crassa mutants altered with respect to nitrogen metabolism.

N S Dunn-Coleman 1, E A Robey 1, A B Tomsett 1, R H Garrett 1
PMCID: PMC369655  PMID: 6152851

Abstract

Glutamate synthase catalyzes glutamate formation from 2-oxoglutarate plus glutamine and plays an essential role when glutamate biosynthesis by glutamate dehydrogenase is not possible. Glutamate synthase activity has been determined in a number of Neurospora crassa mutant strains with various defects in nitrogen metabolism. Of particular interest were two mutants phenotypically mute except in an am (biosynthetic nicotinamide adenine dinucleotide phosphate-glutamate dehydrogenase deficient, glutamate requiring) background. These mutants, i and en-am, are so-called enhancers of am; they have been redesignated herein as en(am)-1 and en(am)-2, respectively. Although glutamate synthase levels in en(am)-1 were essentially wild type, the en(am)-2 strain was devoid of glutamate synthase activity under all conditions examined, suggesting that en(am)-2 may be the structural locus for glutamate synthase. Regulation of glutamate synthase occurred to some extent, presumably in response to glutamate requirements. Glutamate starvation, as in am mutants, led to enhanced activity. In contrast, glutamine limitation, as in gln-1 mutants, depressed glutamate synthase levels.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Boland M. J., Benny A. G. Enzymes of nitrogen metabolism in legume nodules. Purification and properties of NADH-dependent glutamate synthase from lupin nodules. Eur J Biochem. 1977 Oct 3;79(2):355–362. doi: 10.1111/j.1432-1033.1977.tb11816.x. [DOI] [PubMed] [Google Scholar]
  2. Brown C. M., Burn V. J., Johnson B. Presence of glutamate synthase in fission yeasts and its possible role in ammonia assimilation. Nat New Biol. 1973 Nov 28;246(152):115–116. doi: 10.1038/newbio246115a0. [DOI] [PubMed] [Google Scholar]
  3. Dantzig A. H., Wiegmann F. L., Jr, Nason A. Regulation of glutamate dehydrogenases in nit-2 and am mutants of Neurospora crassa. J Bacteriol. 1979 Mar;137(3):1333–1339. doi: 10.1128/jb.137.3.1333-1339.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Dantzig A. H., Zurowski W. K., Ball T. M., Nason A. Induction and repression of nitrate reductase in Neurospora crassa. J Bacteriol. 1978 Feb;133(2):671–679. doi: 10.1128/jb.133.2.671-679.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Deshpande K. L., Kane J. F. Glutamate synthase from Bacillus subtilis: in vitro reconstitution of an active amidotransferase. Biochem Biophys Res Commun. 1980 Mar 13;93(1):308–314. doi: 10.1016/s0006-291x(80)80281-6. [DOI] [PubMed] [Google Scholar]
  6. Dávila G., Sánchez F., Palacios R., Mora J. Genetics and physiology of Neurospora crassa glutamine auxotrophs. J Bacteriol. 1978 Jun;134(3):693–698. doi: 10.1128/jb.134.3.693-698.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. FINCHAM J. R. S. The occurrence of glutamic dehydrogenase in Neurospora an its apparent absence in certain mutant strains. J Gen Microbiol. 1951 Oct;5(4):793–806. doi: 10.1099/00221287-5-4-793. [DOI] [PubMed] [Google Scholar]
  8. Ferguson A. R., Sims A. P. The regulation of glutamine metabolism in Candida utilis: the inactivation of glutamine synthetase. J Gen Microbiol. 1974 Jan;80(1):173–185. doi: 10.1099/00221287-80-1-173. [DOI] [PubMed] [Google Scholar]
  9. Garrett R. H., Nason A. Involvement of a B-type cytochrome in the assimilatory nitrate reductase of Neurospora crassa. Proc Natl Acad Sci U S A. 1967 Oct;58(4):1603–1610. doi: 10.1073/pnas.58.4.1603. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Geary L. E., Meister A. On the mechanism of glutamine-dependent reductive amination of alpha-ketoglutarate catalyzed by glutamate synthase. J Biol Chem. 1977 May 25;252(10):3501–3508. [PubMed] [Google Scholar]
  11. Greenbaum P., Prodouz K. N., Garrett R. H. Preparation and some properties of homogeneous Neurospora crassa assimilatory NADPH-nitrite reductase. Biochim Biophys Acta. 1978 Sep 11;526(1):52–64. doi: 10.1016/0005-2744(78)90289-9. [DOI] [PubMed] [Google Scholar]
  12. Hemmilä I. A., Mäntsälä P. I. Purification and properties of glutamate synthase and glutamate dehydrogenase from Bacillus megaterium. Biochem J. 1978 Jul 1;173(1):45–52. doi: 10.1042/bj1730045. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Hummelt G., Mora J. NADH-dependent glutamate synthase and nitrogen metabolism in Neurospora crassa. Biochem Biophys Res Commun. 1980 Jan 15;92(1):127–133. doi: 10.1016/0006-291x(80)91529-6. [DOI] [PubMed] [Google Scholar]
  14. LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
  15. Lea P. J., Miflin B. J. Alternative route for nitrogen assimilation in higher plants. Nature. 1974 Oct 18;251(5476):614–616. doi: 10.1038/251614a0. [DOI] [PubMed] [Google Scholar]
  16. Miller R. E., Stadtman E. R. Glutamate synthase from Escherichia coli. An iron-sulfide flavoprotein. J Biol Chem. 1972 Nov 25;247(22):7407–7419. [PubMed] [Google Scholar]
  17. Mäntsälä P., Zalkin H. Glutamate synthase. Properties of the glutamine-dependent activity. J Biol Chem. 1976 Jun 10;251(11):3294–3299. [PubMed] [Google Scholar]
  18. Mäntsälä P., Zalkin H. Properties of apoglutamate synthase and comparison with glutamate dehydrogenase. J Biol Chem. 1976 Jun 10;251(11):3300–3305. [PubMed] [Google Scholar]
  19. Premakumar R., Sorger G. J., Gooden D. Repression of nitrate reductase in Neurospora studied by using L-methionine-DL-sulfoximine and glutamine auxotroph gln-1b. J Bacteriol. 1980 Jul;143(1):411–415. doi: 10.1128/jb.143.1.411-415.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Roon R. J., Even H. L., Larimore F. Glutamate synthase: properties of the reduced nicotinamide adenine dinucleotide-dependent enzyme from Saccharomyces cerevisiae. J Bacteriol. 1974 Apr;118(1):89–95. doi: 10.1128/jb.118.1.89-95.1974. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Tempest D. W., Meers J. L., Brown C. M. Synthesis of glutamate in Aerobacter aerogenes by a hitherto unknown route. Biochem J. 1970 Apr;117(2):405–407. doi: 10.1042/bj1170405. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Trotta P. P., Platzer K. E., Haschemeyer R. H., Meister A. Glutamine-binding subunit of glutamate synthase and partial reactions catalyzed by this glutamine amidotransferase. Proc Natl Acad Sci U S A. 1974 Nov;71(11):4607–4611. doi: 10.1073/pnas.71.11.4607. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Tyler B. Regulation of the assimilation of nitrogen compounds. Annu Rev Biochem. 1978;47:1127–1162. doi: 10.1146/annurev.bi.47.070178.005403. [DOI] [PubMed] [Google Scholar]

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