Archives of Microbiology

, Volume 173, Issue 1, pp 1–9 | Cite as

Nickel transport systems in microorganisms

  • T. Eitinger
  • M. -A. Mandrand-Berthelot


The transition metal Ni is an essential cofactor for a number of enzymatic reactions in both prokaryotes and eukaryotes. Molecular analyses have revealed the existence of two major types of high-affinity Ni2+ transporters in bacteria. The Nik system of Escherichia coli is a member of the ABC transporter family and provides Ni2+ ion for the anaerobic biosynthesis of hydrogenases. The periplasmic binding protein of the transporter, NikA, is likely to play a dual role. It acts as the primary binder in the uptake process and is also involved in negative chemotaxis to escape Ni overload. Expression of the nik operon is controlled by the Ni-responsive repressor NikR, which shows functional similarity to the ferric ion uptake regulator Fur. The second type of Ni2+ transporter is represented by HoxN of Ralstonia eutropha, the prototype of a novel family of transition metal permeases. Members of this family have been identified in gram-negative and gram-positive bacteria and recently also in a fission yeast. They transport Ni2+ with very high affinity, but differ with regard to specificity. Site-directed mutagenesis experiments have identified residues that are essential for transport. Besides these uptake systems, different types of metal export systems, which prevent microorganisms from the toxic effects of Ni2+ at elevated intracellular concentrations, have also been described.

Key words Metal ion transport ABC transporter Permease family Metalloregulatory protein Nickel-containing enzymes Metal resistance 


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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • T. Eitinger
    • 1
  • M. -A. Mandrand-Berthelot
    • 2
  1. 1.Humboldt-Universität zu Berlin, Institut für Biologie/Mikrobiologie, Chausseestrasse 117, 10115 Berlin, Germany e-mail:, Tel.: +49-30-20938103, Fax: +49-30-20938102DE
  2. 2.Laboratoire de Génétique Moléculaire des Microorganismes et des Interactions Cellulaires, CNRS UMR 5577, Institut National des Sciences Appliquées, Bât. 406, 20 avenue Albert Einstein, 69621 Villeurbanne Cedex, France e-mail:, Tel.: +33-4-72438191; Fax: +33-4-72438714FR

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