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The Enterococcus hirae paradigm of copper homeostasis: Copper chaperone turnover, interactions, and transactions

Huat Lu, Zen ; Dameron, Charles ; Solioz, Marc

In: Biometals, 2003, vol. 16, no. 1, p. 137-143

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    Titre
    • The Enterococcus hirae paradigm of copper homeostasis: Copper chaperone turnover, interactions, and transactions
    Auteur
    • Huat Lu, Zen. Dept. of Clinical Pharmacology, University of Berne, 3010, Berne, Switzerland
    • Dameron, Charles. Dept. of Chemistry and Biochemistry, Duquesne University, 15282, Pittsburgh, PA, USA
    • Solioz, Marc. Dept. of Clinical Pharmacology, University of Berne, 3010, Berne, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Biometals, 2003, vol. 16, no. 1, p. 137-143. Kluwer Academic Publishers
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:311370
    Summary
    The cop operon is a key element of copper homeostasis in Enterococcus hirae. It encodes two copper ATPases, CopA and CopB, the CopY repressor, and the CopZ metallochaperone. The cop operon is induced by copper, which allows uncompromised growth in up to 5mM ambient copper. Copper uptake appears to be accomplished by the CopA ATPase, a member of the heavy metal CPx-type ATPases and closely related to the human Menkes and Wilson ATPases. The related CopB ATPase extrudes copper when it reaches toxic levels. Intracellular copper routing is accomplished by the CopZ copper chaperone. Using surface plasmon resonance analysis, it was demonstrated that CopZ interacts with the CopA ATPase where it probably becomes copper loaded. CopZ in turn can donate copper to the copper responsive repressor CopY, thereby releasing it from DNA. In high copper, CopZ is proteolyzed. Cell extracts were found to contain a copper activated proteolytic activity that degrades CopZ in vitro. This post-translational control of CopZ expression presumably serves to avoid the accumulation of detrimental Cu-CopZ levels