title: Saccharomyces cerevisiae and Neurospora crassa contain heavy metal sequestering phytochelatin.
abstract: In fungi, cellular resistance to heavy metal cytotoxicity is mediated either by binding of metal ions to proteins of the metallothionein type or by chelation to phytochelatin-peptides of the general formula (gamma-Glu-Cys)n-Gly. Hitherto, only one fungus, Candida glabrata has been shown to contain both metal inactivating systems. Here we show by unambiguous FAB-MS analysis that both a metallothionein-free mutant of Saccharomyces cerevisiae as well as a wildtype strain synthesize phytochelatin (PC2) upon exposure to 250 microM Cd2+ ions. The presence of Zn and/or Cu ions in the nutrient broth also induces PC2 synthesis in this organism. By 109Cd exchange and subsequent monobromobimane fluorescence HPLC, it could be shown that the presence of Cd2+ in the growth medium also induces phytochelatin synthesis in Neurospora crassa, which contains metallothioneins.
authors.affiliation: Lehrstuhl für Pharmazeutische Biologie, Universität München, Federal Republic of Germany.
authors.forename: R
authors.initials: R
authors.lastname: Kneer
authors.forename: T M
authors.initials: TM
authors.lastname: Kutchan
authors.forename: A
authors.initials: A
authors.lastname: Hochberger
authors.forename: M H
authors.initials: MH
authors.lastname: Zenk
mesh_terms: D002104:Cadmium / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D003300:Copper / Q000494:pharmacology; D003470:Culture Media; D005978:Glutathione; D008667:Metalloproteins / Q000032:analysis / Q000096:biosynthesis*; D009154:Mutation; D009492:Neurospora crassa / Q000737:chemistry / Q000378:metabolism*; D054811:Phytochelatins; D010940:Plant Proteins / Q000032:analysis / Q000096:biosynthesis*; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016339:Spectrometry, Mass, Fast Atom Bombardment; D015032:Zinc / Q000494:pharmacology
chemical_list: D003470:Culture Media; D008667:Metalloproteins; D010940:Plant Proteins; D002104:Cadmium; D003300:Copper; D054811:Phytochelatins; D005978:Glutathione; D015032:Zinc