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Identification of an iron-hepcidin complex

  • Sebastien Farnaud
    ,
  • Chiara Rapisarda
    ,
  • Tam Bui
    ,
  • Alex F. Drake
    ,
  • Richard Cammack
    ,
  • Robert W Evans
  • King's College London
Research Output: Contribution to journal Article Peer-review

Abstract

Following its identification as a liver-expressed antimicrobial peptide, the hepcidin peptide was later shown to be a key player in iron homoeostasis. It is now proposed to be the 'iron hormone' which, by interacting with the iron transporter ferroportin, prevents further iron import into the circulatory system. This conclusion was reached using the corresponding synthetic peptide, emphasizing the functional importance of the mature 25-mer peptide, but omitting the possible functionality of its maturation. From urine-purified native hepcidin, we recently demonstrated that a proportion of the purified hepcidin had formed iron-hepcidin complexes. This interaction was investigated further by computer modelling and, based on the sequence similarity of hepcidin with metallothionein, a three-dimensional model of hepcidin, containing one atom of iron, was constructed. To characterize these complexes further, the interaction with iron was analysed using different spectroscopic methods. Monoferric hepcidin was identified by MS, as were possibly other complexes containing two and three atoms of iron respectively, although these were present only in minor amounts. UV/visible absorbance and CD studies identified the iron-binding events which were facilitated at a physiological pH. EPR spectroscopy identified the ferric state of the bound metal, and indicated that the iron-hepcidin complex shares some similarities with the rubredoxin iron-sulfur complex, suggesting the presence of Fe(3+) in a tetrahedral sulfur co-ordination. The potential roles of iron binding for hepcidin are discussed, and we propose either a regulatory function in the maturation of pro-hepcidin into active hepcidin or as the necessary link in the interaction between hepcidin and ferroportin.

Publication Information

Output type

Research Output: Contribution to journal Article Peer-review

Original language

English

Pages from-to (Number of pages)

Pages 555-557

Journal (Volume, Issue Number)

Biochemical Journal (Volume 413, Issue 3)

Publication milestones

  • Published - 01/08/2008

Publication status

Published - 01/08/2008

ISSN

0264-6021

External Publication IDs

  • handle.net: 10547/593392
  • Scopus: 48249118438

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