Reactions of aqueous iron–DFOB (desferrioxamine B) complexes with flavin mononucleotide in the absence of strong iron(II) chelators

Kim, Dongwook; Duckworth, Owen W.; Strathmann, Timothy J.

doi:10.1016/j.gca.2009.12.020

Cited by 20 publications

(24 citation statements)

References 58 publications

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“…If some of the DFOB complexes inner-spherically to surface Fe(III), then this would impart additional negative charge to the surface and likely lead to greater Fe(II) uptake. A second possibility is that the Fe(II) could be reoxidized by DFOB to form a monoamide-DFOB fragment (Farkas et al, 2001;Kim et al, 2009Kim et al, , 2010. However, we did not detect a monoamide-DFOB fragment (m/z = 545) or its Fe(III) complex (m/z = 598) in our samples.…”

Section: Macroscopic Data On the Dissolution Of Goethite In The Presementioning

confidence: 62%

Evidence for ligand hydrolysis and Fe(III) reduction in the dissolution of goethite by desferrioxamine-B

Simanova

Persson

Loring

2010

Geochimica et Cosmochimica Acta

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Section: Macroscopic Data On the Dissolution Of Goethite In The Presementioning

confidence: 62%

Evidence for ligand hydrolysis and Fe(III) reduction in the dissolution of goethite by desferrioxamine-B

Simanova

Persson

Loring

2010

Geochimica et Cosmochimica Acta

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“…103 Fig. 8 shows a plot of log K versus z/IR for DFOB and rhizoferrin, yielding estimated log K + Cr(III)HDFOB ¼ 30.6 and 77 Stability constants for DFOB 35,36,38,40,44,89,106,110,111 and rhizoferrin 71,73,81,112 are taken from the literature and corrected to I ¼ 0 using the Davies equation. 113 Error bars for Cr(III)-siderophore complexes and uncertainty estimates on the regression line are calculated from the 95% confidence interval of the best-fit regression lines.…”

Section: Effect Of Siderophore Complexation On Chromium Mobilitymentioning

confidence: 99%

Siderophore-promoted dissolution of chromium from hydroxide minerals

Duckworth

Akafia

Andrews

et al. 2014

Environ. Sci.: Processes Impacts

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Biomolecules have significant impacts on the fate and transport of contaminant metals in soils and natural waters. Siderophores, Fe(iii)-binding agents that are exuded by microbes and plants, may form strong complexes with and promote the dissolution of contaminant metal ions, such as Co(iii), U(iv), or Pu(iv). Although aqueous Cr(iii)-siderophore complexes have been recognized in the laboratory setting for almost 40 years, few studies have explored interactions of siderophores with Cr-bearing minerals or considered their impacts on environmental chemistry. To better understand the possible effects of siderophores on chromium mobility, we conducted a series of dissolution experiments to quantify the dissolution rates of Cr(iii)(OH)3 in the presence of hydroxamate, catecholate, and α-hydroxycarboxylate siderophores over a range of environmentally relevant pH values. At pH = 5, dissolution rates in the presence of siderophores are similar to control experiments, suggesting a predominantly proton-promoted dissolution mechanism. At pH = 8, the sorption of the siderophores desferrioxamine B and rhizoferrin can be modeled by using Langmuir isotherms. The dissolution rates for these siderophores are proportional to the surface concentrations of sorbed siderophore, and extended X-ray absorption fine structure spectra of dissolution products indicates the formation of Cr(iii)HDFOB(+) and Cr(iii)rhizoferrin(3-) complexes, suggesting a ligand-promoted dissolution mechanism at alkaline pH. Because siderophores promote Cr(iii)(OH)3 dissolution at rates similar in magnitude to those of iron hydroxides and the resulting Cr(iii)-siderophore complexes may be persistent in solution, siderophores could potentially contribute to the mobilization of Cr in soils and sediments where it is abundant due to geological or anthropogenic sources.

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“…For DFO this yields a soluble Fe fraction of ~ 100 nmol L -1 . Experiments have shown that DFO is a very strong Fe complexing agent (Cheah et al 2003;Cheah et al 2006;Kim et al 2010), and consequently DFO has been used extensively to limit Fe availability to phytoplankton in incubation experiments (Hutchins et al 1999). At a 1:1 ratio between ligand and 55 Fe, slightly more than 80% of the 55 Fe was organically complexed by DFO and passed equally through all ultrafiltration membranes and the 0.02 µm Anotop syringe filter.…”

Section: Discussionmentioning

confidence: 99%

Vivaspin ultrafiltration: A new approach for high resolution measurements of colloidal and soluble iron species

Schlösser

Streu

Croot

2013

Limnology & Ocean Methods

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Vivaspin6® ultrafiltration units with molecular weight "cut-off" membranes of 5, 10, 30, 50, and 100 kDa were used together to examine the size distribution of newly formed iron (Fe) colloids in natural seawater samples and in the presence of several different Fe chelators with varying Fe binding strength. Artificial Fe chelators, such as TAC, and 2 kDG, when added at equimolar levels to Fe, supported the formation of a continuum of Fe-ligand colloids between 5 and 100 kDa. More than 90% of the added 55 Fe in these solutions occurred in Fe aggregates/particles larger than 100 kDa. The strong siderophore DFO held the majority of the added 55 Fe in the "truly" soluble fraction ≤ 5 kDa, whereas 90% of 55 Fe added to UV-irradiated seawater was converted into Fe colloids with a size between 50 to 100 kDa (5-6 nm). Membranes with ≥ 10 kDa showed similar "cut-off" properties on natural seawater samples collected in the water column off the Peruvian coast. Fe solubility determined with these membranes was approximately six times greater than Fe solubility determined with the 5 kDa membrane and the 0.02 µm syringe filters. This suggests that a seamless size continuum of organic chelators (≤5 kDa-10 kDa) is present in these seawaters and that estimates of ligand production based on 0.02 µm Anotop solubility experiments underestimates the abundance of soluble/colloidal ligands. Regarding these results, we recommend the use of Vivaspin 5 kDa membranes to separate the "truly" soluble from the colloidal Fe fraction.

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Reactions of aqueous iron–DFOB (desferrioxamine B) complexes with flavin mononucleotide in the absence of strong iron(II) chelators

Cited by 20 publications

References 58 publications

Evidence for ligand hydrolysis and Fe(III) reduction in the dissolution of goethite by desferrioxamine-B

Evidence for ligand hydrolysis and Fe(III) reduction in the dissolution of goethite by desferrioxamine-B

Siderophore-promoted dissolution of chromium from hydroxide minerals

Vivaspin ultrafiltration: A new approach for high resolution measurements of colloidal and soluble iron species

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