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Ternary complex formation facilitates a redox mechanism for iron release from a siderophore.

Publication ,  Journal Article
Mies, KA; Wirgau, JI; Crumbliss, AL
Published in: Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine
April 2006

While the naturally occurring reducing agents glutathione (GSH) and ascorbate (H2A) alone are ineffective at reducing iron(III) sequestered by the siderophore ferrioxamine B, the addition of an iron(II) chelator, sulfonated bathophenanthroline (BPDS), facilitates reduction by either reducing agent. A mechanism is described in which a ternary complex is formed between ferrioxamine B and BPDS in a rapidly established pre-equilibrium step, which is followed by rate limiting reduction of the ternary complex by glutathione or ascorbate. Spectral, thermodynamic, and kinetic evidence are given for ternary complex formation. Ascorbate was found to be slightly more efficient at reducing the ternary complex than glutathione (k4=2.1 x 10(-3) M(-1) s(-1) and k4=6.3 x 10(-4) M(-1) s(-1), respectively) at pH 7. Reduction is followed by a rapid ligand exchange step where iron is released from ferrioxamine B to form tris-(BPDS)iron(II). The implications of these results for siderophore mediated iron transport and release are discussed.

Duke Scholars

Published In

Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine

DOI

EISSN

1572-8773

ISSN

0966-0844

Publication Date

April 2006

Volume

19

Issue

2

Start / End Page

115 / 126

Related Subject Headings

  • Thermodynamics
  • Siderophores
  • Phenanthrolines
  • Oxidation-Reduction
  • Molecular Structure
  • Models, Chemical
  • Kinetics
  • Iron Chelating Agents
  • Iron
  • Glutathione
 

Citation

APA
Chicago
ICMJE
MLA
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Mies, K. A., Wirgau, J. I., & Crumbliss, A. L. (2006). Ternary complex formation facilitates a redox mechanism for iron release from a siderophore. Biometals : An International Journal on the Role of Metal Ions in Biology, Biochemistry, and Medicine, 19(2), 115–126. https://doi.org/10.1007/s10534-005-4342-1
Mies, Kassy A., Joseph I. Wirgau, and Alvin L. Crumbliss. “Ternary complex formation facilitates a redox mechanism for iron release from a siderophore.Biometals : An International Journal on the Role of Metal Ions in Biology, Biochemistry, and Medicine 19, no. 2 (April 2006): 115–26. https://doi.org/10.1007/s10534-005-4342-1.
Mies KA, Wirgau JI, Crumbliss AL. Ternary complex formation facilitates a redox mechanism for iron release from a siderophore. Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine. 2006 Apr;19(2):115–26.
Mies, Kassy A., et al. “Ternary complex formation facilitates a redox mechanism for iron release from a siderophore.Biometals : An International Journal on the Role of Metal Ions in Biology, Biochemistry, and Medicine, vol. 19, no. 2, Apr. 2006, pp. 115–26. Epmc, doi:10.1007/s10534-005-4342-1.
Mies KA, Wirgau JI, Crumbliss AL. Ternary complex formation facilitates a redox mechanism for iron release from a siderophore. Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine. 2006 Apr;19(2):115–126.
Journal cover image

Published In

Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine

DOI

EISSN

1572-8773

ISSN

0966-0844

Publication Date

April 2006

Volume

19

Issue

2

Start / End Page

115 / 126

Related Subject Headings

  • Thermodynamics
  • Siderophores
  • Phenanthrolines
  • Oxidation-Reduction
  • Molecular Structure
  • Models, Chemical
  • Kinetics
  • Iron Chelating Agents
  • Iron
  • Glutathione