Divalent metal ions induce conformational change in pure, human wild-type p53 tumor suppressor protein.
The ability of wild-type and not mutant p53 to exert antiproliferative effects on normal cells may be related to a difference in the conformational state of the protein. We have used pure, human wild-type p53 and a panel of monoclonal antibodies whose epitopes map throughout the protein to assess whether divalent metal ions affect the conformation of p53. Our results show that the presence of Zn2+ ions at physiological concentrations, directly reduced or blocked accessibility of epitopes on pure wild-type p53, an effect which was reversed by chelating agents. Loss of epitope reactivity was maximal between the protein mid-region and C-terminus. Analytical sucrose density gradient ultracentrifugation studies also confirmed that Zn(2+)-induced conformational changes partially affected the pattern of p53 oligomerisation. The observed binding of pure p53 to a sequence-specific DNA motif was unaffected by the presence of added Zn2+ ions or metal chelating agents.
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Protein Isolation and Cloning Laboratory, Imperial Cancer Research Fund, London, UK.
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D001483:Base Sequence; D002413:Cations, Divalent / Q000737:chemistry* / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008670:Metals / Q000737:chemistry* / Q000494:pharmacology; D008969:Molecular Sequence Data; D011487:Protein Conformation / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry*; D015032:Zinc / Q000494:pharmacology
D002413:Cations, Divalent; D008670:Metals; D016159:Tumor Suppressor Protein p53; D015032:Zinc