Interference by toxic metal ions with zinc-dependent proteins involved in maintaining genomic stability
| Autor: | Monika Asmuss, Shashi Khandelwal, Gunnar Jahnke, Andrea Hartwig, Holger Blessing, S Hoffmann, Anke Pelzer, Alexander Bürkle |
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| Rok vydání: | 2002 |
| Předmět: |
Protein Folding
DNA Repair DNA repair Cations Divalent Poly ADP ribose polymerase Toxicology medicine.disease_cause chemistry.chemical_compound Metals Heavy medicine Metallothionein Humans N-Glycosyl Hydrolases Chemistry RNA-Binding Proteins Zinc Fingers General Medicine Base excision repair Xeroderma Pigmentosum Group A Protein DNA-Binding Proteins Zinc Biochemistry DNA glycosylase Zinc toxicity DNA Food Science Nucleotide excision repair |
| Zdroj: | Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association. 40(8) |
| ISSN: | 0278-6915 |
| Popis: | Metal ions are essential components of biological systems; nevertheless, even essential elements may have toxic or carcinogenic properties. Thus, besides As(III) and Cd(II), also Ni(II) and Co(II) have been shown previously to disturb different types of DNA repair systems at low, non-cytotoxic concentrations. Since some metals exert high affinities for SH groups, we investigated whether zinc finger structures in DNA-binding motifs of DNA repair proteins are potential targets for toxic metal ions. The bacterial formamidopyrimidine-DNA glycosylase (Fpg protein) involved in base excision repair was inhibited by Cd(II), Cu(II) and Hg(II) with increasing efficiencies, whereas Co(II), As(III), Pb(II) and Ni(II) had no effect. Furthermore, Cd(II) still disturbed enzyme function when bound to metallothionein. Strong inhibition was also observed in the presence of phenylselenyl chloride, followed by selenocystine, while selenomethionine was not inhibitory. Regarding the mammalian XPA protein involved in the recognition of DNA lesions during nucleotide excision repair, its DNA-binding capacity was diminished by Cd(II), Cu(II), Ni(II) and Co(II), while Hg(II), Pb(II) and As(III) were ineffective. Finally, the H(2)O(2)-induced activation of the poly(ADP-ribose)polymerase (PARP) involved in DNA strand break detection and apoptosis was greatly reduced by Cd(II), Co(II), Ni(II) and As(III). Similarly, the disruption of correct p53 folding and DNA binding by Cd(II), Ni(II) and Co(II) has been shown by other authors. Therefore, zinc-dependent proteins involved in DNA repair and cell-cycle control may represent sensitive targets for some toxic metals such as Cd(II), Ni(II), Co(II) and Cu(II), as well as for some selenium compounds. Relevant mechanisms of inhibition appear to be the displacement of zinc by other transition metals as well as redox reactions leading to thiol/disulfide interchange. |
| Databáze: | OpenAIRE |
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