Biochemistry

Peptides to Sway Iron Levels

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Science  14 Sep 2007:
Vol. 317, Issue 5844, pp. 1471
DOI: 10.1126/science.317.5844.1471a

Ferritin proteins are best known for storing iron within their cores, but ferritins also release iron when it is needed, such as during hemoglobin synthesis or when iron is lost through hemorrhage. Although the release process is driven by the reduction of Fe3+ and uptake by Fe2+ chelators or chaperones, changes in the gated pore of the protein, such as mutations of conserved pore residues, affect the rate of iron release, and in vitro, millimolar concentrations of urea can unfold pore helices and increase the release rate. Liu et al. searched a combinatorial peptide library of ferritin-binding peptides and identified a single heptamer that accelerated iron release threefold, and when combined with Desferal, an iron chelator in therapeutic use, led to an eightfold increase. Another heptapeptide was identified that decreased iron release, possibly by binding across the pore. Potential applications include treatment of iron overload or limiting unwanted effects of iron release, such as consumption of cellular reductants. — PDS

J. Biol. Chem. 282, 10.1074/jbc.C700153200 (2007).

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