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Monomeric yeast frataxin is an iron-binding protein.

Publication ,  Journal Article
Cook, JD; Bencze, KZ; Jankovic, AD; Crater, AK; Busch, CN; Bradley, PB; Stemmler, AJ; Spaller, MR; Stemmler, TL
Published in: Biochemistry
June 2006

Friedreich's ataxia, an autosomal cardio- and neurodegenerative disorder that affects 1 in 50,000 humans, is caused by decreased levels of the protein frataxin. Although frataxin is nuclear-encoded, it is targeted to the mitochondrial matrix and necessary for proper regulation of cellular iron homeostasis. Frataxin is required for the cellular production of both heme and iron-sulfur (Fe-S) clusters. Monomeric frataxin binds with high affinity to ferrochelatase, the enzyme involved in iron insertion into porphyrin during heme production. Monomeric frataxin also binds to Isu, the scaffold protein required for assembly of Fe-S cluster intermediates. These processes (heme and Fe-S cluster assembly) share requirements for iron, suggesting that monomeric frataxin might function as the common iron donor. To provide a molecular basis to better understand frataxin's function, we have characterized the binding properties and metal-site structure of ferrous iron bound to monomeric yeast frataxin. Yeast frataxin is stable as an iron-loaded monomer, and the protein can bind two ferrous iron atoms with micromolar binding affinity. Frataxin amino acids affected by the presence of iron are localized within conserved acidic patches located on the surfaces of both helix-1 and strand-1. Under anaerobic conditions, bound metal is stable in the high-spin ferrous state. The metal-ligand coordination geometry of both metal-binding sites is consistent with a six-coordinate iron-(oxygen/nitrogen) based ligand geometry, surely constructed in part from carboxylate and possibly imidazole side chains coming from residues within these conserved acidic patches on the protein. On the basis of our results, we have developed a model for how we believe yeast frataxin interacts with iron.

Duke Scholars

Published In

Biochemistry

DOI

EISSN

1520-4995

ISSN

0006-2960

Publication Date

June 2006

Volume

45

Issue

25

Start / End Page

7767 / 7777

Related Subject Headings

  • Thermodynamics
  • Saccharomyces cerevisiae Proteins
  • Nuclear Magnetic Resonance, Biomolecular
  • Models, Molecular
  • Mass Spectrometry
  • Iron-Binding Proteins
  • Iron
  • Frataxin
  • Chromatography, Gel
  • Biochemistry & Molecular Biology
 

Citation

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Cook, J. D., Bencze, K. Z., Jankovic, A. D., Crater, A. K., Busch, C. N., Bradley, P. B., … Stemmler, T. L. (2006). Monomeric yeast frataxin is an iron-binding protein. Biochemistry, 45(25), 7767–7777. https://doi.org/10.1021/bi060424r
Cook, Jeremy D., Krisztina Z. Bencze, Ana D. Jankovic, Anna K. Crater, Courtney N. Busch, Patrick B. Bradley, Ann J. Stemmler, Mark R. Spaller, and Timothy L. Stemmler. “Monomeric yeast frataxin is an iron-binding protein.Biochemistry 45, no. 25 (June 2006): 7767–77. https://doi.org/10.1021/bi060424r.
Cook JD, Bencze KZ, Jankovic AD, Crater AK, Busch CN, Bradley PB, et al. Monomeric yeast frataxin is an iron-binding protein. Biochemistry. 2006 Jun;45(25):7767–77.
Cook, Jeremy D., et al. “Monomeric yeast frataxin is an iron-binding protein.Biochemistry, vol. 45, no. 25, June 2006, pp. 7767–77. Epmc, doi:10.1021/bi060424r.
Cook JD, Bencze KZ, Jankovic AD, Crater AK, Busch CN, Bradley PB, Stemmler AJ, Spaller MR, Stemmler TL. Monomeric yeast frataxin is an iron-binding protein. Biochemistry. 2006 Jun;45(25):7767–7777.
Journal cover image

Published In

Biochemistry

DOI

EISSN

1520-4995

ISSN

0006-2960

Publication Date

June 2006

Volume

45

Issue

25

Start / End Page

7767 / 7777

Related Subject Headings

  • Thermodynamics
  • Saccharomyces cerevisiae Proteins
  • Nuclear Magnetic Resonance, Biomolecular
  • Models, Molecular
  • Mass Spectrometry
  • Iron-Binding Proteins
  • Iron
  • Frataxin
  • Chromatography, Gel
  • Biochemistry & Molecular Biology