The Dps protein of Escherichia coli is involved in copper homeostasis

Microbiol Res. 2010 Feb 28;165(2):108-15. doi: 10.1016/j.micres.2008.12.003. Epub 2009 Feb 20.

Abstract

The DNA-binding protein of starved cells (Dps) has two distinct cellular functions in Escherichia coli. The spherical Dps dodecamer can store iron and, predominantly in the stationary growth phase, high amounts of Dps protein protect the genome by binding non-specifically to DNA. In this study we investigated the role of Dps in copper homeostasis in growing cells of E. coli. Under reductive aerobic growth conditions that favor a redox shift from Cu(II) to Cu(I) or under anaerobiosis, cells deleted in dps were sensitive to low copper ion concentrations. Deletion of the DNA-binding N-terminus of Dps did not abrogate protection against copper toxicity indicating protection against copper stress is not directly related to DNA binding of Dps. The Dps protein is not a copper-storage protein in vitro or in vivo. In contrast, cells lacking Dps exhibited increased cellular copper concentrations compared to their wild-type parent. Furthermore, overproduction of Dps during growth phase resulted in decreased intracellular copper content under copper stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aerobiosis
  • Anaerobiosis
  • Bacterial Outer Membrane Proteins / genetics
  • Bacterial Outer Membrane Proteins / physiology*
  • Copper / metabolism*
  • Escherichia coli / physiology*
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / physiology*
  • Gene Deletion
  • Homeostasis*
  • Oxidation-Reduction

Substances

  • Bacterial Outer Membrane Proteins
  • Escherichia coli Proteins
  • dps protein, E coli
  • Copper