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Kinetics and mechanism of iron(III) dissociation from the dihydroxamate siderophores alcaligin and rhodotorulic acid.

Publication ,  Journal Article
Boukhalfa, H; Brickman, TJ; Armstrong, SK; Crumbliss, AL
Published in: Inorganic chemistry
December 2000

The kinetics and mechanism of siderophore ligand dissociation from their fully chelated Fe(III) complexes is described for the highly preorganized cyclic tetradentate alcaligin and random linear tetradentate rhodotorulic acid in aqueous solution at 25 degrees C (Fe2L3 + 6H+ reversible 2 Fe3+ aq + 3 H2L). At siderophore:Fe(III) ratios where Fe(III) is hexacoordinated, kinetic data for the H(+)-driven ligand dissociation from the Fe2L3 species is consistent with a singly ligand bridged structure for both the alcaligin and rhodotorulic acid complexes. Proton-driven ligand dissociation is found to proceed via parallel reaction paths for rhodotorulic acid, in contrast with the single path previously observed for the linear trihydroxamate siderophore ferrioxamine B. Parallel paths are also available for ligand dissociation from Fe2(alcaligin)3, although the efficiency of one path is greatly diminished and dissociation of the bis coordinated complex Fe(alcaligin)(OH2)2+ is extremely slow (k = 10(-5) M-1 s-1) due to the high degree of preorganization in the alcaligin siderophore. Mechanistic interpretations were further confirmed by investigating the kinetics of ligand dissociation from the ternary complexes Fe(alcaligin)(L) in aqueous acid where L = N-methylacetohydroxamic acid and glycine hydroxamic acid. The existence of multiple ligand dissociation paths is discussed in the context of siderophore mediated microbial iron transport.

Duke Scholars

Published In

Inorganic chemistry

DOI

EISSN

1520-510X

ISSN

0020-1669

Publication Date

December 2000

Volume

39

Issue

25

Start / End Page

5591 / 5602

Related Subject Headings

  • Siderophores
  • Piperazines
  • Molecular Conformation
  • Models, Molecular
  • Kinetics
  • Iron
  • Inorganic & Nuclear Chemistry
  • Hydroxamic Acids
  • 3403 Macromolecular and materials chemistry
  • 3402 Inorganic chemistry
 

Citation

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Boukhalfa, H., Brickman, T. J., Armstrong, S. K., & Crumbliss, A. L. (2000). Kinetics and mechanism of iron(III) dissociation from the dihydroxamate siderophores alcaligin and rhodotorulic acid. Inorganic Chemistry, 39(25), 5591–5602. https://doi.org/10.1021/ic000330k
Boukhalfa, H., T. J. Brickman, S. K. Armstrong, and A. L. Crumbliss. “Kinetics and mechanism of iron(III) dissociation from the dihydroxamate siderophores alcaligin and rhodotorulic acid.Inorganic Chemistry 39, no. 25 (December 2000): 5591–5602. https://doi.org/10.1021/ic000330k.
Boukhalfa H, Brickman TJ, Armstrong SK, Crumbliss AL. Kinetics and mechanism of iron(III) dissociation from the dihydroxamate siderophores alcaligin and rhodotorulic acid. Inorganic chemistry. 2000 Dec;39(25):5591–602.
Boukhalfa, H., et al. “Kinetics and mechanism of iron(III) dissociation from the dihydroxamate siderophores alcaligin and rhodotorulic acid.Inorganic Chemistry, vol. 39, no. 25, Dec. 2000, pp. 5591–602. Epmc, doi:10.1021/ic000330k.
Boukhalfa H, Brickman TJ, Armstrong SK, Crumbliss AL. Kinetics and mechanism of iron(III) dissociation from the dihydroxamate siderophores alcaligin and rhodotorulic acid. Inorganic chemistry. 2000 Dec;39(25):5591–5602.
Journal cover image

Published In

Inorganic chemistry

DOI

EISSN

1520-510X

ISSN

0020-1669

Publication Date

December 2000

Volume

39

Issue

25

Start / End Page

5591 / 5602

Related Subject Headings

  • Siderophores
  • Piperazines
  • Molecular Conformation
  • Models, Molecular
  • Kinetics
  • Iron
  • Inorganic & Nuclear Chemistry
  • Hydroxamic Acids
  • 3403 Macromolecular and materials chemistry
  • 3402 Inorganic chemistry