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. 1995 Apr;7(4):463–471. doi: 10.1105/tpc.7.4.463

Inhibition of the glycine decarboxylase multienzyme complex by the host-selective toxin victorin.

D A Navarre 1, T J Wolpert 1
PMCID: PMC160796  PMID: 7773018

Abstract

Victoria blight of oats is caused by the fungus Cochliobolus victoriae. This fungus is pathogenic due to its ability to produce the host-selective toxin victorin. We previously identified a 100-kD protein that binds victorin in vivo only in susceptible genotypes and a 15-kD protein that binds victorin in vivo in both susceptible and resistant genotypes. Recently, we determined that the oat 100-kD victorin binding protein is the P protein of the glycine decarboxylase complex (GDC). In this study, we examined the effect of victorin on glycine decarboxylase activity (GDA). Victorin was a potent in vivo inhibitor of GDA. Leaf slices pretreated for 2 hr with victorin displayed an effective concentration for 50% inhibition (EC50) of 81 pM for GDA. Victorin inhibited the glycine-bicarbonate exchange reaction in vitro with an EC50 of 23 microM. We also identified a 15-kD mitochondrial protein that bound victorin in a ligand-specific manner. Based on amino acid sequence analysis, we concluded that the 15-kD mitochondrial protein is the H protein component of the GDC. Thus, victorin specifically binds to two components of the GDC. GDA in resistant tissue treated with 100 micrograms/mL victorin for 5 hr was inhibited 26%, presumably as a consequence of the interaction of victorin with the H protein. Victorin had no detectable effect on GDA in isolated mitochondria, apparently due to the inability of isolated mitochondria to import victorin. These results suggest that the interaction of victorin with the GDC is central to victorin's mode of action.

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Selected References

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  1. Akimitsu K., Hart L. P., Walton J. D., Hollingsworth R. Covalent binding sites of victorin in oat leaf tissues detected by anti-victorin polyclonal antibodies. Plant Physiol. 1992 Jan;98(1):121–126. doi: 10.1104/pp.98.1.121. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bourguignon J., Macherel D., Neuburger M., Douce R. Isolation, characterization, and sequence analysis of a cDNA clone encoding L-protein, the dihydrolipoamide dehydrogenase component of the glycine cleavage system from pea-leaf mitochondria. Eur J Biochem. 1992 Mar 1;204(2):865–873. doi: 10.1111/j.1432-1033.1992.tb16706.x. [DOI] [PubMed] [Google Scholar]
  3. Bourguignon J., Neuburger M., Douce R. Resolution and characterization of the glycine-cleavage reaction in pea leaf mitochondria. Properties of the forward reaction catalysed by glycine decarboxylase and serine hydroxymethyltransferase. Biochem J. 1988 Oct 1;255(1):169–178. doi: 10.1042/bj2550169. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1016/0003-2697(76)90527-3. [DOI] [PubMed] [Google Scholar]
  5. Kim Y., Oliver D. J. Molecular cloning, transcriptional characterization, and sequencing of cDNA encoding the H-protein of the mitochondrial glycine decarboxylase complex in peas. J Biol Chem. 1990 Jan 15;265(2):848–853. [PubMed] [Google Scholar]
  6. Kume A., Kure S., Tada K., Hiraga K. The impaired expression of glycine decarboxylase in patients with hyperglycinemias. Biochem Biophys Res Commun. 1988 Jul 15;154(1):292–297. doi: 10.1016/0006-291x(88)90683-3. [DOI] [PubMed] [Google Scholar]
  7. Meehan F., Murphy H. C. A New Helminthosporium Blight of Oats. Science. 1946 Nov 1;104(2705):413–414. doi: 10.1126/science.104.2705.413. [DOI] [PubMed] [Google Scholar]
  8. Neuburger M., Jourdain A., Douce R. Isolation of H-protein loaded with methylamine as a transient species in glycine decarboxylase reactions. Biochem J. 1991 Sep 15;278(Pt 3):765–769. doi: 10.1042/bj2780765. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Oliver D. J., Neuburger M., Bourguignon J., Douce R. Interaction between the Component Enzymes of the Glycine Decarboxylase Multienzyme Complex. Plant Physiol. 1990 Oct;94(2):833–839. doi: 10.1104/pp.94.2.833. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Sarojini G., Oliver D. J. Extraction and partial characterization of the glycine decarboxylase multienzyme complex from pea leaf mitochondria. Plant Physiol. 1983 May;72(1):194–199. doi: 10.1104/pp.72.1.194. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Scheffer R. P., Livingston R. S. Host-selective toxins and their role in plant diseases. Science. 1984 Jan 6;223(4631):17–21. doi: 10.1126/science.223.4631.17. [DOI] [PubMed] [Google Scholar]
  12. Somerville C. R., Ogren W. L. Mutants of the cruciferous plant Arabidopsis thaliana lacking glycine decarboxylase activity. Biochem J. 1982 Feb 15;202(2):373–380. doi: 10.1042/bj2020373. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Srinivasan R., Oliver D. J. H-Protein of the Glycine Decarboxylase Multienzyme Complex : Complementary DNA Encoding the Protein from Arabidopsis thaliana. Plant Physiol. 1992 Apr;98(4):1518–1519. doi: 10.1104/pp.98.4.1518. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Ullrich C. I., Novacky A. J. Electrical Membrane Properties of Leaves, Roots, and Single Root Cap Cells of Susceptible Avena sativa: Effect of Victorin C. Plant Physiol. 1991 Mar;95(3):675–681. doi: 10.1104/pp.95.3.675. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Walker J. L., Oliver D. J. Light-induced increases in the glycine decarboxylase multienzyme complex from pea leaf mitochondria. Arch Biochem Biophys. 1986 Aug 1;248(2):626–638. doi: 10.1016/0003-9861(86)90517-5. [DOI] [PubMed] [Google Scholar]
  16. Wheeler H., Hanchey P. J. Respiratory control: loss in mitochondria from diseased plants. Science. 1966 Dec 23;154(3756):1569–1571. doi: 10.1126/science.154.3756.1569. [DOI] [PubMed] [Google Scholar]
  17. Wilson R. L., Stauffer L. T., Stauffer G. V. Roles of the GcvA and PurR proteins in negative regulation of the Escherichia coli glycine cleavage enzyme system. J Bacteriol. 1993 Aug;175(16):5129–5134. doi: 10.1128/jb.175.16.5129-5134.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Wolpert T. J., Macko V., Acklin W., Arigoni D. Molecular Features Affecting the Biological Activity of the Host-Selective Toxins from Cochliobolus victoriae. Plant Physiol. 1988 Sep;88(1):37–41. doi: 10.1104/pp.88.1.37. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Wolpert T. J., Macko V. Specific binding of victorin to a 100-kDa protein from oats. Proc Natl Acad Sci U S A. 1989 Jun;86(11):4092–4096. doi: 10.1073/pnas.86.11.4092. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Wolpert T. J., Navarre D. A., Moore D. L., Macko V. Identification of the 100-kD victorin binding protein from oats. Plant Cell. 1994 Aug;6(8):1145–1155. doi: 10.1105/tpc.6.8.1145. [DOI] [PMC free article] [PubMed] [Google Scholar]

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