Bacterial zinc transporters and regulators

Biometals. Sep-Dec 2001;14(3-4):239-49. doi: 10.1023/a:1012984713391.

Abstract

Zn2+ homeostasis in bacteria is achieved by export systems and uptake systems which are separately regulated by their own regulators. Three types of Zn2+ export systems that protect cells from high toxic concentrations of Zn2+ have been identified: RND multi-drug efflux transporters, P-type ATPases, and cation-diffusion facilitators. The RND type exporters for Zn2+ are only found in a few gram-negative bacteria; they allow a very efficient export across the cytoplasmic membrane and the outer membrane of the cell. P-type ATPases and cation-diffusion facilitators belong to protein families that are also found in eukaryotes. The exporters are regulated in bacteria by MerR-like repressor/activators or by ArsR-like repressors. For the high-affinity uptake of Zn2+, several binding-protein-dependent ABC transporters belonging to one class have been identified in different bacteria. Zn2+ ABC transporters are regulated by Zur repressors, which belong to the Fur protein family of iron regulators. Little is known about low-affinity Zn2+ uptake under zinc-replete conditions. One known example is the phosphate uptake system Pit, which may cotransport Zn2+ in Escherichia coli. Similarly, the citrate-metal cotransporter CitM in Bacillus subtilis may help to supply Zn2+.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • ATP-Binding Cassette Transporters / genetics
  • ATP-Binding Cassette Transporters / metabolism
  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / metabolism
  • Amino Acid Sequence
  • Bacteria / genetics
  • Bacteria / metabolism*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Ion Transport
  • Models, Biological
  • Molecular Sequence Data
  • Sequence Homology, Amino Acid
  • Zinc / metabolism*

Substances

  • ATP-Binding Cassette Transporters
  • Bacterial Proteins
  • Carrier Proteins
  • zinc-binding protein
  • Adenosine Triphosphatases
  • Zinc