Cadystin a and b, major unit peptides comprising cadmium binding peptides induced in a fission yeast ----- separation, revision of structures and synthesis

Kondo, Naoto; Imai, Kunio; Isobe, Mitsuaki; Goto, Toshio; Murasugi, Akira; Wada-Nakagawa, Chiaki; Hayashi, Yukimasa

doi:10.1016/s0040-4039(01)91190-6

Cited by 157 publications

(83 citation statements)

References 6 publications

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“…Phytochelatins (PCs) are enzymatically synthesized peptides in plants that usually consist of three amino acids: glutamic acid (Glu), cysteine (Cys) and glycine (Gly) (Kondo et al, 1984;Grill et al, 1985). The resultant glutathione (GSH) molecule (γ-Glu-Cys)-Gly is transformed into PC by γ-glutamylcysteine dipeptidyl transpeptidase (phytochelatin synthase, EC 2.3.2.15), forming the general structural formula of (γ-Glu-Cys) n -Gly, where n ranges from 2-11 (Grill et al, 1985;1987;.…”

Section: Introductionmentioning

confidence: 99%

Reduced translocation of cadmium from roots is associated with increased production of phytochelatins and their precursors

Akhter

McGarvey

Macfie

2012

Journal of Plant Physiology

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SummaryCadmium (Cd) is a non-essential trace element and its environmental concentrations are approaching toxic levels, especially in some agricultural soils. Understanding how and where Cd is stored in plants is important for ensuring food safety. In this study, we examined two plant species that differ in the distribution of Cd among roots and leaves. Lettuce and barley were grown in nutrient solution under two conditions: chronic (4 week) exposure to a low, environmentally relevant concentration (1.0 µM) of Cd and acute (1 h) exposure to a high concentration (5.0 mM) of Cd. Seedlings grown in solution containing 1.0 µM CdCl 2 did not show symptoms of toxicity and, at this concentration, 77% of the total Cd was translocated to leaves of lettuce, whereas only 24% of the total Cd was translocated to barley leaves. We tested the hypothesis that differential accumulation of Cd in roots and leaves is related to differential concentrations of phytochelatins (PCs), and its precursor peptides. The amounts of PCs and their precursor peptides in the roots and shoots were measured using HPLC. Each of PC 2-4 was synthesized in the barley root upon chronic exposure to Cd and did not increase further upon acute exposure. In the case of lettuce, no PCs were detected in the root given either Cd treatment.The high amounts of PCs produced in barley root could have contributed to preferential retention of Cd in barley roots.

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Section: Introductionmentioning

confidence: 99%

Reduced translocation of cadmium from roots is associated with increased production of phytochelatins and their precursors

Akhter

McGarvey

Macfie

2012

Journal of Plant Physiology

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“…The PCs produced by S. pombe have a structure identical to those of plants, consisting 2Abbreviations: PC, phytochelatin; HMW, high mol wt; LMW, low mol wt; S-2, sulfide. from 2 to 11 (9,14,15). The number of repeating units varies with the conditions of Cd exposure (12,16).…”

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confidence: 99%

Brassica juncea Produces a Phytochelatin-Cadmium-Sulfide Complex

Speiser¹,

Abrahamson²,

Bañuelos³

et al. 1992

Plant Physiol.

106

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Phytochelatins (PCs) are enzymically synthesized peptides produced in higher plants and some fungi upon exposure to heavy metals. We have examined PC production in the Se-tolerant wild mustard Brassica juncea and found that it produces two types of PC-Cd complexes with the same characteristics as those from fission yeast Schizosaccharomyces pombe, including a high molecular weight PC-Cd-sulfide form.Heavy metals, a group of elements including Cd, Cu, Zn, Bi, Ni, Hg, and Pb, are toxic to all organisms at varying concentrations. In response to those elements, animal cells and some fungi, including Saccharomyces cerevisiae and Neurospora crassa, synthesize metal-chelating proteins called metallothioneins (11, 13). In contrast, the fission yeast Schizosaccharomyces pombe, algae, and higher plants synthesize enzymically produced peptides as a result of exposure to these metals. These metal-binding peptides have been called PC,2 cadystins, Cd-peptides, y(EC),-G, and y-glutamyl peptides; they will be referred to here, as in recent reviews (24,28,30), as PCs. PCs were first discovered in the fission yeast as components of metal-containing complexes from Cd-induced cells (19,20); it was demonstrated that previous reports of metallothionein-like proteins from plants could be attributed to PCs (9) and that PCs were produced by all higher plants tested (7). PCs have also been shown to exist in the algae Chlorella fusca (6) and the yeast Candida glabrata, which produces both PCs and a metallothionein (17,18). PC synthesis is induced by a variety of metals, including

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“…The absence of Cd-peptide does not limit Cd-accumulation in the system studied. Results suggest that tobacco suspension cells accommodate the presence of non-growth-inhibiting and growth-inhibiting levels of Cd and Zn by sequestration in the vacuole as complexes with endogenous organic acids and that this may be a principal means for accommodation of Cd as well as Zn in the presence and absence of Cd-peptide.Recent interest in unique (-y-Glu-Cys), Gly Cd-binding peptides, also called cadystins, phytochelatins, etc., centers on their structure, biosynthesis, and possible role in tolerance of plants and plant cultured cells to challenge with high levels of this metal (4,6,9,16,20,21,24,31 Prior to the demonstration that plants exposed to high levels of Cd form Cd-peptide, models to explain the mechanisms of heavy metal tolerance in plants focused on Zn and Cu and possible roles of the cell wall and vacuolar organic acids in metal sequestration (32). Ernst was first to postulate vacuolar accumulation of Zn organic acid complexes as a mechanism for Zn tolerance in naturally tolerant ecotypes (32).…”

mentioning

confidence: 99%

“…peptides, also called cadystins, phytochelatins, etc., centers on their structure, biosynthesis, and possible role in tolerance of plants and plant cultured cells to challenge with high levels of this metal (4,6,9,16,20,21,24,31 and references therein). While the amino acid composition and primary structure of this family of peptides is becoming understood for several higher plant systems and certain yeasts, their function(s), selectivity in binding metals, aggregation potential, mode of biosynthesis, and metal selectivity and concentration dependence in their induction, are not understood (31).…”

mentioning

confidence: 99%

Relationships between Cadmium, Zinc, Cd-Peptide, and Organic Acid in Tobacco Suspension Cells

Krotz¹,

Evangelou²,

Wagner³

1989

Plant Physiol.

144

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Responses of tobacco (Nicotiana tabacum) suspension cells to Cd and Zn were studied in the presence and absence of ligand of Cd-peptide in order to understand the role of this peptide versus other mechanisms in Cd and Zn accumulation and accommodation in plants. With 45 micromolar Cd and 300 micromolar Zn (non-growth-inhibiting levels), metals appeared rapidly within cells, and intracellular Cd and Zn reached medium concentrations after 6 to 10 hours. Cd-peptide was observed in response to Cd after 2 hours, but this form only accounted for -30% of soluble Cd after 24 hours. Peptide was not observed in cells exposed to 300 micromolar Zn for up to 7 days. Organic acid-to-metal stoichiometry indicated that endogenous organic acid content of cells was more than sufficient to complex absorbed metals and no evidence was found for stimulation of organic acid biosynthesis by Cd or Zn. Metal-complexing potential of organic acids for Cd and Zn versus endogenous cations is discussed as is vacuolarextravacuolar distribution of metals. The absence of Cd-peptide does not limit Cd-accumulation in the system studied. Results suggest that tobacco suspension cells accommodate the presence of non-growth-inhibiting and growth-inhibiting levels of Cd and Zn by sequestration in the vacuole as complexes with endogenous organic acids and that this may be a principal means for accommodation of Cd as well as Zn in the presence and absence of Cd-peptide.Recent interest in unique (-y-Glu-Cys), Gly Cd-binding peptides, also called cadystins, phytochelatins, etc., centers on their structure, biosynthesis, and possible role in tolerance of plants and plant cultured cells to challenge with high levels of this metal (4,6,9,16,20,21,24,31 Prior to the demonstration that plants exposed to high levels of Cd form Cd-peptide, models to explain the mechanisms of heavy metal tolerance in plants focused on Zn and Cu and possible roles of the cell wall and vacuolar organic acids in metal sequestration (32). Ernst was first to postulate vacuolar accumulation of Zn organic acid complexes as a mechanism for Zn tolerance in naturally tolerant ecotypes (32). Considerable, but not entirely consistent, evidence exists for a correlation between Zn content and organic acid content in various plants and cultured cells (2,8,13,15,25,26,32 Other extraction media and methods were used as noted. A previously described procedure was used to determine Cdpeptide content (18). Homogenates were centrifuged (4°C) at 16,000g for 5 min and the resulting supernatants were centrifuged at 100,000g, 30 min. Pellets were combined and washed with growth media less metal; insoluble fractions were dried and digested with 9:1 (v/v) HNO3:HClO4 and the digest was evaporated and analyzed for Cd and Zn content in 1 % HCI using flame atomic absorption spectroscopy (with background correction for Zn). For determination of K+, Mg2+, Ca2+, NO3-, C1-, S042-, PO34, and H+, water washed cells were homogenized in freshly boiled, distilled, deionized H20. The K+, Mg2+, and Ca2+ contents ...

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Cadystin a and b, major unit peptides comprising cadmium binding peptides induced in a fission yeast ----- separation, revision of structures and synthesis

Cited by 157 publications

References 6 publications

Reduced translocation of cadmium from roots is associated with increased production of phytochelatins and their precursors

Reduced translocation of cadmium from roots is associated with increased production of phytochelatins and their precursors

Brassica juncea Produces a Phytochelatin-Cadmium-Sulfide Complex

Relationships between Cadmium, Zinc, Cd-Peptide, and Organic Acid in Tobacco Suspension Cells

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