Untitled

Harwani, Sailesh; Roginsky, Alexandra; Vallejo, Yolanda; Castignetti, Domenic

doi:10.1023/a:1018303912151

Cited by 8 publications

(3 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The mass spectra of the samples containing degradation products and the complex of Mn(III) formed by these products did not show dominant products (data not shown), but instead showed many peaks with m /z = 200−400. This result is consistent with the hydrolytic cleaving of DFOB observed during microbial degradation ( − ), except that the redox reaction in our study yields many different degradation products.…”

Section: Discussionsupporting

confidence: 92%

Siderophore−Manganese(III) Interactions. I. Air-Oxidation of Manganese(II) Promoted by Desferrioxamine B

Duckworth

Sposito

2005

Environ. Sci. Technol.

137

157

View full text Add to dashboard Cite

Recent studies suggest that aqueous Mn(ll) complexes, particularly those with non-carboxylated ligands such as microbial siderophores, may be stable in soil and aquatic environments. In this paper, we determine the stability constants for Mn(ll) and Mn(lll) complexes with the common trihydroxamate siderophore, desferrioxamine B (DFOB). Base and redox titrations were conducted to determine DFOB conditional protonation constants and conditional stability constants for 1:1 DFOB complexes with Mn(ll) and Mn(lll). The conditional protonation constants agree well with literature values. We determined stability constants for three Mn(ll)-DFOB species and one Mn(lll)-DFOB species at 25 degrees C in 0.1 M NaCl. The Mn(lll) HDFOB+ complex can be formed readily by air-oxidation of Mn(ll)-DFOB. This reaction exhibits pseudo first-order kinetics with a rate coefficient that can be characterized as the product of oxygen concentration with a linear combination of the concentrations of the three Mn(ll)-DFOB complexes. The second-order rate coefficients appearing in this linear combination are 1 to 2 orders of magnitude smaller than that associated with oxidation of the hydrolytic species Mn(OH)(0)2. The Mn(lll)HDFOB+ complex is stable for pH in the range of 7.0-11.3; but, at pH < 7.0 it decomposes by internal electron transfer, yielding oxidized DFOB products and Mn(ll). For p[H+] > 11.3, the complex degrades by disproportionation, yielding Mn(ll) and solid MnO2. This range of pH stability supports the hypothesis that aqueous Mn(lll) may play a vital role in the biogeochemical cycling of not only manganese, but also other elements, such as carbon, sulfur, nitrogen, oxygen, and redox-active metals.

show abstract

Section: Discussionsupporting

confidence: 92%

Siderophore−Manganese(III) Interactions. I. Air-Oxidation of Manganese(II) Promoted by Desferrioxamine B

Duckworth

Sposito

2005

Environ. Sci. Technol.

137

157

View full text Add to dashboard Cite

show abstract

“…In our experiments, this can be approximated to be z ≤ 3 based on the ratio of [Mn(II)] eff to [DFOB] inf , as shown in Table . Because DFOB contains many possible sites for an oxidation reaction to occur ( , ), oxidized fragments of DFOB may contain moieties that are susceptible to further oxidation, allowing them to react multiple times ( z ) with the MnOOH surface before a stable aqueous species is produced. It would be useful to determine the products of DFOB oxidation; however, because of the possibility of multiple reaction pathways, the overall oxidation of DFOB by manganite may result in many different products.…”

Section: Resultsmentioning

confidence: 99%

Siderophore−Manganese(III) Interactions II. Manganite Dissolution Promoted by Desferrioxamine B

Duckworth

Sposito

2005

Environ. Sci. Technol.

110

View full text Add to dashboard Cite

Recent laboratory and field studies suggest that Mn(lll) forms persistent aqueous complexes with high-affinity ligands. Aqueous Mn(lll) species thus may play a significant but largely unexplored role in biogeochemical processes. One formation mechanism for these species is the dissolution of Mn(lll)-bearing minerals. To investigate this mechanism, we measured the steady-state dissolution rates of manganite (gamma-MnOOH) in the presence of desferrioxamine B (DFOB), a common trihydroxamate siderophore. We find that DFOB dissolves manganite by both reductive and nonreductive reaction pathways. For pH > 6.5, a nonreductive ligand-promoted reaction is the dominant dissolution pathway, with a steady-state dissolution rate proportional to the surface concentration of DFOB. In the absence of reductants, the aqueous Mn(lIl)HDFOB+ complex resulting from dissolution is stable for at least several weeks at circumneutral to alkaline pH and at 25 degrees C. For pH < 6.5, Mn2+ is the dominant aqueous species resulting from manganite dissolution, implicating a reductive dissolution pathway. These results have important implications for the biogeochemical cycling of both manganese and siderophores--as well as Fe(lll)--in natural waters and soils.

show abstract

“…The amidase from a different DFOB-degrading organism, classified as a Rhizobium loti -like bacterium, was determined to be a serine protease-like amidase . These amidases have been found to be active only toward DFOB and are unable to hydrolyze FOB . The coding of TonB-dependent receptors on the N. irakense genome suggests the bacterium could garner dual benefit from DFOB as an alternative source of carbon, and as a source of iron through FOB xenosiderophore uptake pathways.…”

Section: Enzyme-mediated Catabolism (Reverse Biosynthesis) Of Dfobmentioning

confidence: 99%

Advances in the Chemical Biology of Desferrioxamine B

et al. 2017

View full text Add to dashboard Cite

Desferrioxamine B (DFOB) was discovered in the late 1950s as a hydroxamic acid metabolite of the soil bacterium Streptomyces pilosus. The exquisite affinity of DFOB for Fe(III) identified its potential for removing excess iron from patients with transfusion-dependent hemoglobin disorders. Many studies have used semisynthetic chemistry to produce DFOB adducts with new properties and broad-ranging functions. More recent approaches in chemical biology have revealed some nuances of DFOB biosynthesis and discovered new DFOB-derived drugs and radiometal imaging agents. The current and potential applications of DFOB continue to inspire a rich body of chemical biology research focused on this bacterial metabolite.

show abstract

Untitled

Cited by 8 publications

References 24 publications

Siderophore−Manganese(III) Interactions. I. Air-Oxidation of Manganese(II) Promoted by Desferrioxamine B

Siderophore−Manganese(III) Interactions. I. Air-Oxidation of Manganese(II) Promoted by Desferrioxamine B

Siderophore−Manganese(III) Interactions II. Manganite Dissolution Promoted by Desferrioxamine B

Advances in the Chemical Biology of Desferrioxamine B

Contact Info

Product

Resources

About