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Article: Arabidopsis HMA2, a Divalent Heavy Metal-Transporting P^sub IB^-Type ATPase, Is Involved in Cytoplasmic Zn^sup 2+^ Homeostasis1
- Article from:
- Plant Physiology
- Article date:
- November 1, 2004
- Author:
CopyrightCopyright American Society of Plant Physiologists Nov 2004. Provided by ProQuest LLC. (Hide copyright information)
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P^sup IB^-type ATPases transport heavy metal ions (Cu^sup +^, Cu^sup 2+^, Zn^sup 2+^, Cd^sup 2+^, Co^sup 2+^, etc.) across biological membranes. Several members of this subfamily are present in plants. Higher plants are the only eukaryotes where putative Zn^sup 2+^-ATPases have been identified. We have cloned HMA2, a P^sup IB^-ATPase present in Arabidopsis (Arabidopsis thaliana), and functionally characterized this enzyme after heterologous expression in yeast (Saccharomyces cerevisiae). HMA2 is a Zn^sup 2+^-dependent ATPase that is also activated by Cd^sup 2+^ and, to a lesser extent, by other divalent heavy metals (Pb^sup 2+^, Ni^sup 2+^, Cu^sup 2+^, and Co^sup 2+^). The enzyme forms an ...