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. 1995 Apr;107(4):1293–1301. doi: 10.1104/pp.107.4.1293

MgATP-Dependent Transport of Phytochelatins Across the Tonoplast of Oat Roots.

D E Salt 1, W E Rauser 1
PMCID: PMC157264  PMID: 12228436

Abstract

In Cd-exposed oat (Avena sativa) roots Cd was found to be associated primarily with the phytochelatin ([gamma]-glutamylcysteinyl)3-glutamic acid [([gamma]EC)3G], with a peptide to Cd ratio of 1:3 (cysteine to Cd ratio of 1:1), even though both ([gamma]EC)2G and ([gamma]EC)3G were present in the roots. Phytochelatins are known to accumulate in the vacuoles of plant cells on exposure to Cd, but the mechanism is not clear. Here we present evidence for the transport of the phytochelatins ([gamma]EC)3G and ([gamma]EC)2G as well as the Cd complex Cd-([gamma]EC)3G across the tonoplast of oat roots. Transport of ([gamma]EC)3G had a Km, for MgATP of 0.18 mM and a Vmax of 0.7 to 1 nmol mg-1 protein min-1. Transport of ([gamma]EC)3G was also energized by MgGTP and to a lesser extent MgUTP and was highly sensitive to orthovanadate, with a 50%-inhibitory concentration of 0.9 [mu]M. The Cd complex Cd-([gamma]EC)3G and ([gamma]EC)2G were also transported in a MgATP-dependent, vanadate-sensitive manner. Therefore, this process is a candidate for the transport of both phytochelatins, and Cd as its peptide complex, from the cytoplasm into the vacuole.

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Selected References

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  1. Bensadoun A., Weinstein D. Assay of proteins in the presence of interfering materials. Anal Biochem. 1976 Jan;70(1):241–250. doi: 10.1016/s0003-2697(76)80064-4. [DOI] [PubMed] [Google Scholar]
  2. Churchill K. A., Sze H. Anion-sensitive, h-pumping ATPase in membrane vesicles from oat roots. Plant Physiol. 1983 Mar;71(3):610–617. doi: 10.1104/pp.71.3.610. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Endicott J. A., Ling V. The biochemistry of P-glycoprotein-mediated multidrug resistance. Annu Rev Biochem. 1989;58:137–171. doi: 10.1146/annurev.bi.58.070189.001033. [DOI] [PubMed] [Google Scholar]
  4. Gottesman M. M., Pastan I. Biochemistry of multidrug resistance mediated by the multidrug transporter. Annu Rev Biochem. 1993;62:385–427. doi: 10.1146/annurev.bi.62.070193.002125. [DOI] [PubMed] [Google Scholar]
  5. Grill E., Winnacker E. L., Zenk M. H. Phytochelatins: the principal heavy-metal complexing peptides of higher plants. Science. 1985 Nov 8;230(4726):674–676. doi: 10.1126/science.230.4726.674. [DOI] [PubMed] [Google Scholar]
  6. Juranka P. F., Zastawny R. L., Ling V. P-glycoprotein: multidrug-resistance and a superfamily of membrane-associated transport proteins. FASEB J. 1989 Dec;3(14):2583–2592. doi: 10.1096/fasebj.3.14.2574119. [DOI] [PubMed] [Google Scholar]
  7. Kamimoto Y., Gatmaitan Z., Hsu J., Arias I. M. The function of Gp170, the multidrug resistance gene product, in rat liver canalicular membrane vesicles. J Biol Chem. 1989 Jul 15;264(20):11693–11698. [PubMed] [Google Scholar]
  8. Krotz R. M., Evangelou B. P., Wagner G. J. Relationships between Cadmium, Zinc, Cd-Peptide, and Organic Acid in Tobacco Suspension Cells. Plant Physiol. 1989 Oct;91(2):780–787. doi: 10.1104/pp.91.2.780. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Meuwly P., Thibault P., Rauser W. E. gamma-Glutamylcysteinylglutamic acid--a new homologue of glutathione in maize seedlings exposed to cadmium. FEBS Lett. 1993 Dec 28;336(3):472–476. doi: 10.1016/0014-5793(93)80858-r. [DOI] [PubMed] [Google Scholar]
  10. Moreno S., Nurse P. Clues to action of cdc25 protein. Nature. 1991 May 16;351(6323):194–194. doi: 10.1038/351194b0. [DOI] [PubMed] [Google Scholar]
  11. Randall S. K., Sze H. Properties of the partially purified tonoplast H+-pumping ATPase from oat roots. J Biol Chem. 1986 Jan 25;261(3):1364–1371. [PubMed] [Google Scholar]
  12. Rauser W. E. Cadmium-binding peptides from plants. Methods Enzymol. 1991;205:319–333. doi: 10.1016/0076-6879(91)05114-b. [DOI] [PubMed] [Google Scholar]
  13. Rauser W. E. Phytochelatins. Annu Rev Biochem. 1990;59:61–86. doi: 10.1146/annurev.bi.59.070190.000425. [DOI] [PubMed] [Google Scholar]
  14. Salt D. E., Wagner G. J. Cadmium transport across tonoplast of vesicles from oat roots. Evidence for a Cd2+/H+ antiport activity. J Biol Chem. 1993 Jun 15;268(17):12297–12302. [PubMed] [Google Scholar]
  15. Vögeli-Lange R., Wagner G. J. Subcellular localization of cadmium and cadmium-binding peptides in tobacco leaves : implication of a transport function for cadmium-binding peptides. Plant Physiol. 1990 Apr;92(4):1086–1093. doi: 10.1104/pp.92.4.1086. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Wang Y., Sze H. Similarities and differences between the tonoplast-type and the mitochondrial H+-ATPases of oat roots. J Biol Chem. 1985 Sep 5;260(19):10434–10443. [PubMed] [Google Scholar]

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