AtPCS1, a Phytochelatin Synthase from Arabidopsis: Isolation and in vitro Reconstitution

Phytochelatins, a class of posttranslationally synthesized peptides, play a pivotal role in heavy metal, primarily Cd2+ tolerance in plants and fungi by chelating these substances and decreasing their free concentrations. Derived from glutathione and related thiols by the action of γ -glutamylcystei...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 1999-06, Vol.96 (12), p.7110-7115
Main Authors: Vatamaniuk, Olena K., Mari, Stéphane, Lu, Yu-Ping, Rea, Philip A.
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Aminoacyltransferases - genetics
Aminoacyltransferases - isolation & purification
Aminoacyltransferases - metabolism
Arabidopsis - enzymology
Arabidopsis thaliana
Biological Sciences
Biology
Cell growth
Chromatography
Complementary DNA
Dialysis
Enzymes
Flowers & plants
Genes
Heavy metals
Metals
Molecular Sequence Data
Peptides
Plant Proteins - genetics
Plant Proteins - isolation & purification
Plant Proteins - metabolism
Proteins
Radioactive decay
RNA
Saccharomyces cerevisiae
Sequence Alignment
Thiols
Yeasts
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Summary:Phytochelatins, a class of posttranslationally synthesized peptides, play a pivotal role in heavy metal, primarily Cd2+ tolerance in plants and fungi by chelating these substances and decreasing their free concentrations. Derived from glutathione and related thiols by the action of γ -glutamylcysteine dipeptidyl transpeptidases (phytochelatin synthases; EC 2.3.2.15), phytochelatins consist of repeating units of γ -glutamylcysteine followed by a C-terminal Gly, Ser, or β -Ala residue [poly-(γ -Glu-Cys)n-Xaa]. Here we report the suppression cloning of a cDNA (AtPCS1) from Arabidopsis thaliana encoding a 55-kDa soluble protein that enhances heavy-metal tolerance and elicits Cd2+-activated phytochelatin accumulation when expressed in Saccharomyces cerevisiae. On the basis of these properties and the sufficiency of immunoaffinity-purified epitope-tagged AtPCS1 polypeptide for high rates of Cd2+-activated phytochelatin synthesis from glutathione in vitro, AtPCS1 is concluded to encode the enzyme phytochelatin synthase.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.96.12.7110