Phytochelatins are synthesized by two vacuolar serine carboxypeptidases in Saccharomyces cerevisiae.
Phytochelatins (PCs) are cysteine-rich peptides that chelate heavy metal ions, thereby mediating heavy metal tolerance in plants, fission yeast, and Caenorhabditis elegans. They are synthesized from glutathione by PC synthase, a specific dipeptidyltransferase. While Saccharomyces cerevisiae synthesizes PCs upon exposure to heavy metal ions, the S. cerevisiae genome does not encode a PC synthase homologue. How PCs are synthesized in yeast is unclear. This study shows that the vacuolar serine carboxypeptidases CPY and CPC are responsible for PC synthesis in yeast. The finding of a PCS-like activity of these enzymes in vivo discloses another route for PC biosynthesis in eukaryotes.
Wünschmann
Jana
J
Lehrstuhl für Botanik, Technische Universität München, Am Hochanger 4, D-85354 Freising, Germany.
Beck
Andreas
A
Meyer
Laurent
L
Letzel
Thomas
T
Grill
Erwin
E
Lendzian
Klaus J
KJ
D000595:Amino Acid Sequence; D002268:Carboxypeptidases / Q000235:genetics / Q000378:metabolism*; D005978:Glutathione / Q000096:biosynthesis* / Q000235:genetics; D008969:Molecular Sequence Data; D054811:Phytochelatins; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014617:Vacuoles / Q000201:enzymology
D029701:Saccharomyces cerevisiae Proteins; D054811:Phytochelatins; D002268:Carboxypeptidases; C520243:CPC protein, S cerevisiae; C520242:CPY protein, S cerevisiae; D005978:Glutathione