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. 1974 Dec;120(3):1124–1132. doi: 10.1128/jb.120.3.1124-1132.1974

Mis-Regulation of 3-Deoxy-d-Arabino-Heptulosonate 7-Phosphate Synthetase Does Not Account for Growth Inhibition by Phenylalanine in Agmenellum quadruplicatum

Roy A Jensen 1, S Stenmark-Cox 1, Lonnie O Ingram 1
PMCID: PMC245891  PMID: 4215792

Abstract

The growth of the blue-green bacterium, Agmenellum quadruplicatum, is inhibited in the presence of l-phenylalanine. This species has a single, constitutively synthesized 3-deoxy-d-arabino-heptulosonate 7-phosphate (DAHP) synthetase. l-Phenylalanine inhibits DAHP synthetase non-competitively with respect to both substrate reactants. Other aromatic amino acids do not inhibit the activity of DAHP synthetase. A common expectation for branch-point enzymes such as DAHP synthetase is a balanced pattern of feedback control by all of the ultimate end products. It seemed likely that growth inhibition might equate with defective regulation within the branched aromatic pathway. Accordingly, the possibility was examined that mis-regulation of DAHP synthetase by l-phenylalanine in wild-type cells causes starvation for precursors of the other aromatic end products. However, the molecular basis for growth inhibition cannot be attributed to l-phenylalanine inhibition of DAHP synthetase for the following reasons: (i) DAHP synthetase enzymes from l-phenylalanine-resistant mutants are more, rather than less, sensitive to feedback inhibition by l-phenylalanine. (ii) Shikimate not only fails to antagonize inhibition, but is itself inhibitory. (iii) Neither the sensitivity nor the completeness of l-phenylalanine inhibition of the wild-type enzyme in vitro appears sufficient to account for the potent inhibition of growth in vivo by l-phenylalanine. The dominating effect of l-phenylalanine in the control of DAHP synthetase appears to reflect a mechanism that prevents rather than causes growth inhibition by l-phenylalanine. The alteration of the control of DAHP synthetase in mutants selected for resistance to growth inhibition by l-phenylalanine did indicate that the cause for this metabolite vulnerability can be localized within the aromatic amino acid pathway. Apparently, an aromatic intermediate (between shikimate and the end products) accumulates in the presence of l-phenylalanine, causing toxicity by some unknown mechanism. It is concluded that phenylpyruvate, potentially formed by transamination of l-phenylalanine, is an unlikely cause of growth inhibition. Although several significant questions remain unanswered, our results suggest that single-effector control of DAHP synthetase, the first regulatory enzyme activity of a branched pathway, may be more appropriate than it would seem a priori.

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Selected References

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  1. Andrews P. The gel-filtration behaviour of proteins related to their molecular weights over a wide range. Biochem J. 1965 Sep;96(3):595–606. doi: 10.1042/bj0960595. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Borichewski R. M. Keto acids as growth-limiting factors in autotrophic growth of Thiobacillus thiooxidans. J Bacteriol. 1967 Feb;93(2):597–599. doi: 10.1128/jb.93.2.597-599.1967. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Carminatti H., Jiménez de Asúa L., Leiderman B., Rozengurt E. Allosteric properties of skeletal muscle pyruvate kinase. J Biol Chem. 1971 Dec 10;246(23):7284–7288. [PubMed] [Google Scholar]
  4. Eccleston M., Kelly D. P. Assimilation and toxicity of exogenous amino acids in the methane-oxidizing bacterium Methylococcus capsulatus. J Gen Microbiol. 1972 Aug;71(3):541–554. doi: 10.1099/00221287-71-3-541. [DOI] [PubMed] [Google Scholar]
  5. Ingram L. O., Pierson D., Kane J. F., Van Baalen C., Jensen R. A. Documentation of auxotrophic mutation in blue-green bacteria: characterization of a tryptophan auxotroph in Agmenellum quadruplicatum. J Bacteriol. 1972 Jul;111(1):112–118. doi: 10.1128/jb.111.1.112-118.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Jensen R. A., Calhoun D. H., Stenmark S. L. Allosteric inhibition of 3-deoxy-D-arabino-heptulosonate 7-phosphate synthetase by tyrosine, tryptophan and phenylpyruvate in Pseudomonas aeruginosa. Biochim Biophys Acta. 1973 Jan 12;293(1):256–268. doi: 10.1016/0005-2744(73)90398-7. [DOI] [PubMed] [Google Scholar]
  7. Jensen R. A., Nasser D. S. Comparative regulation of isoenzymic 3-deoxy-D-arabino-heptulosonate 7-phosphate synthetases in microorganisms. J Bacteriol. 1968 Jan;95(1):188–196. doi: 10.1128/jb.95.1.188-196.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Jensen R. A., Nasser D. S., Nester E. W. Comparative control of a branch-point enzyme in microorganisms. J Bacteriol. 1967 Nov;94(5):1582–1593. doi: 10.1128/jb.94.5.1582-1593.1967. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Jensen R. A., Nester E. W. Regulatory enzymes of aromatic amino acid biosynthesis in Bacillus subtilis. I. Purification and properties of 3-deoxy-D-arabino-heptulosonate 7-phosphate synthetase. J Biol Chem. 1966 Jul 25;241(14):3365–3372. [PubMed] [Google Scholar]
  10. Johnson C. L., Vishniac W. Growth Inhibition in Thiobacillus neapolitanus by Histidine, Methionine, Phenylalanine, and Threonine. J Bacteriol. 1970 Dec;104(3):1145–1150. doi: 10.1128/jb.104.3.1145-1150.1970. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Kelly D. P. Autotrophy: concepts of lithotrophic bacteria and their organic metabolism. Annu Rev Microbiol. 1971;25:177–210. doi: 10.1146/annurev.mi.25.100171.001141. [DOI] [PubMed] [Google Scholar]
  12. Kelly D. P. Regulation of chemoautotrophic metabolism. 3. DAHP synthetase in Thiobacillus neapolitanus. Arch Mikrobiol. 1969;69(4):360–369. doi: 10.1007/BF00408576. [DOI] [PubMed] [Google Scholar]
  13. Kelly D. P. Regulation of chemoautotrophic metabolism. I. Toxicity of phenylalanine to thiobacilli. Arch Mikrobiol. 1969;69(4):330–342. doi: 10.1007/BF00408574. [DOI] [PubMed] [Google Scholar]
  14. LEAVITT R. I., UMBARGER H. E. Isoleucine and valine metabolism in Escherichia coli. XI. Valine inhibition of the growth of Escherichia coli strain K-12. J Bacteriol. 1962 Mar;83:624–630. doi: 10.1128/jb.83.3.624-630.1962. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Lu M. C., Matin A., Rittenberg S. C. Inhibition of growth of obligately chemolithotrophic Thiobacilli by amino acids. Arch Mikrobiol. 1971;79(4):354–366. doi: 10.1007/BF00424911. [DOI] [PubMed] [Google Scholar]
  16. Stenmark S. L., Pierson D. L., Jensen R. A., Glover G. I. Blue-green bacteria synthesise L-tyrosine by the pretyrosine pathway. Nature. 1974 Feb 1;247(5439):290–292. doi: 10.1038/247290a0. [DOI] [PubMed] [Google Scholar]
  17. Weber G., Glazer R. I., Ross R. A. Regulation of human and rat brain metabolism: inhibitory action of phenylalanine and phenylpyruvate on glycolysis, protein, lipid, DNA, and RNA metabolism. Adv Enzyme Regul. 1970;8:13–36. doi: 10.1016/0065-2571(70)90006-3. [DOI] [PubMed] [Google Scholar]
  18. Wolfson P. J., Krulwich T. A. Inhibition of isocitrate lyase: the basis for inhibition of growth of two Arthrobacter species by pyruvate. J Bacteriol. 1972 Oct;112(1):356–364. doi: 10.1128/jb.112.1.356-364.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]

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