title: Heavy metal ions are potent inhibitors of protein folding.
abstract: Environmental and occupational exposure to heavy metals such as cadmium, mercury and lead results in severe health hazards including prenatal and developmental defects. The deleterious effects of heavy metal ions have hitherto been attributed to their interactions with specific, particularly susceptible native proteins. Here, we report an as yet undescribed mode of heavy metal toxicity. Cd2+, Hg2+ and Pb2+ proved to inhibit very efficiently the spontaneous refolding of chemically denatured proteins by forming high-affinity multidentate complexes with thiol and other functional groups (IC(50) in the nanomolar range). With similar efficacy, the heavy metal ions inhibited the chaperone-assisted refolding of chemically denatured and heat-denatured proteins. Thus, the toxic effects of heavy metal ions may result as well from their interaction with the more readily accessible functional groups of proteins in nascent and other non-native form. The toxic scope of heavy metals seems to be substantially larger than assumed so far.
authors.affiliation: Biochemisches Institut, Universität Zürich, CH-8057 Zürich, Switzerland.
authors.forename: Sandeep K
authors.initials: SK
authors.lastname: Sharma
authors.forename: Pierre
authors.initials: P
authors.lastname: Goloubinoff
authors.forename: Philipp
authors.initials: P
authors.lastname: Christen
mesh_terms: D000251:Adenosine Triphosphatases / Q000187:drug effects; D002104:Cadmium / Q000633:toxicity*; D002413:Cations, Divalent / Q000494:pharmacology; D007854:Lead / Q000633:toxicity*; D008156:Luciferases / Q000737:chemistry / Q000187:drug effects; D008628:Mercury / Q000633:toxicity*; D019216:Metals, Heavy / Q000633:toxicity*; D018832:Molecular Chaperones / Q000187:drug effects; D017510:Protein Folding; D020673:Protein Renaturation / Q000187:drug effects
chemical_list: D002413:Cations, Divalent; D019216:Metals, Heavy; D018832:Molecular Chaperones; D002104:Cadmium; D007854:Lead; D008156:Luciferases; D000251:Adenosine Triphosphatases; D008628:Mercury