Comparison of the kinetics of iron release from a marine (Trichodesmium erythraeum) Dps protein and mammalian ferritin in the presence and absence of ligands

Madeli Castruita, Lauren A. Elmegreen, Yeala Shaked, Edward I. Stiefel, Francois M. M. Morel

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

The ferritin superfamily of iron storage proteins includes ferritin proper and Dps (DNA binding protein from starved cells) along with bacterioferritin. We examined the release of Fe from the Dps of Trichodesmium erythraeum (Dpstery) and compared it to the release of Fe from horse spleen ferritin (HoSF) under various conditions. Both desferrioxamine B (DFB), a Fe(III) chelator, and ascorbic acid were able to mobilize Fe from Dpstery at rates comparable to those observed for HoSF. The initial Fe release rate from both proteins increased linearly with the concentration of DFB, suggesting that the chelator binds to Fe in the protein. A small but significant rate obtained by extrapolation to zero concentration of DFB implies that Dpstery and HoSF might release Fe(III) spontaneously. A similar result was observed for HoSF in the presence of sulfoxine. In a different experiment, Fe(III) was transferred from holoferritin to apotransferrin across a dialysis membrane in the absence of chelator or reducing agent. The apparent spontaneous release of Fe from HoSF and Dpstery brings forth the hypothesis that the Fe core in Fe storage proteins might be continuously dissolving and re-precipitating in vivo, thus maintaining it in a highly reactive and bioavailable form.

Original languageEnglish (US)
Pages (from-to)1686-1691
Number of pages6
JournalJournal of Inorganic Biochemistry
Volume101
Issue number11-12
DOIs
StatePublished - Nov 1 2007

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Inorganic Chemistry

Keywords

  • Dps
  • Ferritin
  • Iron
  • Iron dissolution
  • Iron storage proteins

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