Transport and detoxification systems for transition metals, heavy metals and metalloids in eukaryotic and prokaryotic microbes.

Abstract

Transition metals, heavy metals and metalloids are usually toxic in excess, but a number of transition metals are essential trace elements. In all cells there are mechanisms for metal ion homeostasis that frequently involve a balance between uptake and efflux systems. This review will briefly describe ATP-coupled resistance pumps. ZntA and CadA are bacterial P-type ATPases that confers resistance to Zn(II), Cd(II) and Pb(II). Homologous copper pumps include the Menkes and Wilson disease proteins and CopA, an Escherichia coli pump that confers resistance to Cu(I). For resistance to arsenicals and antimonials there are several different families of transporters. In E. coli the ArsAB ATPase is a novel system that confers resistance to As(III) and Sb(III). Eukaryotic arsenic resistance transporters include Acr3p and Ycf1p of Saccharomyces cerevisiae. These systems provide resistance to arsenite [As(III)]. Arsenate [As(V)] detoxification involves reduction of As(V) to As(III), a process catalyzed by arsenate reductase enzymes. There are three families of arsenate reductases, two found in bacterial systems and a third identified in S. cerevisiae.

• Authors: Barry P Rosen
• Journal: Comparative biochemistry and physiology. Part A, Molecular & integrative physiology (Comp Biochem Physiol A Mol Integr Physiol) Vol. 133 Issue 3 Pg. 689-93 (Nov 2002) ISSN: 1095-6433 [Print] United States
• PMID: 12443926 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S., Review)

Chemical References

• Metals, Heavy
• Trace Elements

Topics

• Biological Transport (physiology)
• Escherichia coli (metabolism)
• Eukaryotic Cells (metabolism)
• Inactivation, Metabolic (physiology)
• Metals, Heavy (metabolism, toxicity)
• Prokaryotic Cells (metabolism)
• Saccharomyces cerevisiae (metabolism)
• Trace Elements (metabolism, toxicity)