New insights into the solution equilibrium of molybdenum(vi)–hydroxamate systems: 1H and 17O NMR spectroscopic study of Mo(vi)–desferrioxamine B and Mo(vi)–monohydroxamic acid systems

Farkas, Etelka; Csóka, Hajnalka; Tóth, I.

doi:10.1039/b300431g

Cited by 21 publications

(17 citation statements)

References 15 publications

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“…The registered pH-potentiometric titration curves, similarly to the few previous results on Mo(VI)-monohydroxamic acid systems [30], indicated very strong interaction between the studied ligands and Mo(VI), but only under acidic conditions. No difference between the curves for the ligands or those registered in the Mo(VI)-containing samples was observed above pH ca.…”

Section: Resultssupporting

confidence: 83%

Trends and Exceptions in the Interaction of Hydroxamic Acid Derivatives of Common Di- and Tripeptides with Some 3d and 4d Metal Ions in Aqueous Solution

et al. 2019

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By using various techniques (pH-potentiometry, UV-Visible spectrophotometry, 1H and 17O-NMR, EPR, ESI-MS), first time in the literature, solution equilibrium study has been performed on complexes of dipeptide and tripeptide hydroxamic acids—AlaAlaNHOH, AlaAlaN(Me)OH, AlaGlyGlyNHOH, and AlaGlyGlyN(Me)OH—with 4d metals: the essential Mo(VI) and two half-sandwich type cations, [(η6-p-cym)Ru(H2O)3]2+ as well as [(η5-Cp*)Rh(H2O)3]2+, the latter two having potential importance in cancer therapy. The tripeptide derivatives have also been studied with some biologically important 3d metals, such as Fe(III), Ni(II), Cu(II), and Zn(II), in order to compare these new results with the corresponding previously obtained ones on dipeptide hydroxamic acids. Based on the outcomes, the effects of the type of metal ions, the coordination number, the number and types of donor atoms, and their relative positions to each other on the complexation have been evaluated in the present work. We hope that these collected results might be used when a new peptide-based hydroxamic acid molecule is planned with some purpose, e.g., to develop a potential metalloenzyme inhibitor.

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Section: Resultssupporting

confidence: 83%

Trends and Exceptions in the Interaction of Hydroxamic Acid Derivatives of Common Di- and Tripeptides with Some 3d and 4d Metal Ions in Aqueous Solution

et al. 2019

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“…1), which is a surrogate for a metal ion's hardness (Duckworth et al 2009bHernlem et al 1999;Hider 1984). The difficulty in overcoming this trend in affinity in favor of a target metal is illustrated by the Table 1 Selected logb for a selection of metallophores with diverse metal ions Anderegg et al 1963;Bellenger et al 2007;Buglyo et al 1995;Carrano et al 1996;Choi et al 2006;Duckworth et al 2009c;Duckworth and Sposito 2005b;Enyedy et al 2004;Evers et al 1989;Farkas et al 2003;Harrington et al 2012b;Hernlem et al 1996;Jarvis and Hancock 1991;Kim et al 2009;Murakami et al 1989;Pesch et al 2012;Shenker et al 1996;Szabo and Farkas 2011;Whisenhunt et al 1996;Yoshimura et al 2011 …”

Section: Structural Factors Controlling Metallophore Complexation Of mentioning

confidence: 97%

Metallophores and Trace Metal Biogeochemistry

et al. 2014

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Trace metal limitation not only affects the biological function of organisms, but also the health of ecosystems and the global cycling of elements. The enzymatic machinery of microbes helps to drive critical biogeochemical cycles at the macroscale, and in many cases, the function of metalloenzyme-mediated processes may be limited by the scarcity of essential trace metals. In response to these nutrient limitations, some organisms employ a strategy of exuding metallophores, biogenic ligands that facilitate the uptake of metal ions. For example, bacterial, fungal, and graminaceous plant species are known to use Fe(III)-binding siderophores for nutrient acquisition, providing the best known and most thoroughly studied example of metallophores. However, recent breakthroughs have suggested or established the role of metallophores in the uptake of several other metallic nutrients. Furthermore, these metallophores may influence environmental trace metal fate and transport beyond nutrient acquisition. These discoveries have resulted in a deeper understanding of trace metal geochemistry and its relationship to the cycling of carbon and nitrogen in natural systems. In this review, we provide an overview of the current state of knowledge on the biogeochemistry of metallophores in trace metal acquisition, and explore established and potential metallophore systems.Electronic supplementary material The online version of this article (

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“…Unlike A. vinelandii, many soil bacteria produce hydroxamate siderophores, which have a lower affinity for oxoanions than catechol siderophores. DFB, for example, does not bind Mo at neutral pH (Farkas et al 2003). It is possible that the production of siderophores with different oxoanion affinities affect the fitness of N 2 -fixing bacteria in soils with different concentrations of Mo, V and W. In turn, the variability in metal requirements among microorganisms (e.g., high Mo requirement in N 2 -fixing bacteria) and in metal concentrations and speciation in various locals (e.g., Fe oxides vs. Fe-NOM complexes) may explain the variety in siderophore structures found in bacteria.…”

Section: Effect Of Siderophores On Metal Speciation In Soilsmentioning

confidence: 99%

Multiple roles of siderophores in free-living nitrogen-fixing bacteria

et al. 2009

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Free-living nitrogen-fixing bacteria in soils need to tightly regulate their uptake of metals in order to acquire essential metals (such as the nitrogenase metal cofactors Fe, Mo and V) while excluding toxic ones (such as W). They need to do this in a soil environment where metal speciation, and thus metal bioavailability, is dependent on a variety of factors such as organic matter content, mineralogical composition, and pH. Azotobacter vinelandii, a ubiquitous gram-negative soil diazotroph, excretes in its external medium catechol compounds, previously identified as siderophores, that bind a variety of metals in addition to iron. At low concentrations, complexes of essential metals (Fe, Mo, V) with siderophores are taken up by the bacteria through specialized transport systems. The specificity and regulation of these transport systems are such that siderophore binding of excess Mo, V or W effectively detoxifies these metals at high concentrations. In the topsoil (leaf litter layer), where metals are primarily bound to plant-derived organic matter, siderophores extract essential metals from natural ligands and deliver them to the bacteria. This process appears to be a key component of a mutualistic relationship between trees and soil diazotrophs, where tree-produced leaf litter provides a living environment rich in organic matter and micronutrients for nitrogen-fixing bacteria, which in turn supply new nitrogen to the ecosystem.

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New insights into the solution equilibrium of molybdenum(vi)–hydroxamate systems: 1H and 17O NMR spectroscopic study of Mo(vi)–desferrioxamine B and Mo(vi)–monohydroxamic acid systems

Cited by 21 publications

References 15 publications

Trends and Exceptions in the Interaction of Hydroxamic Acid Derivatives of Common Di- and Tripeptides with Some 3d and 4d Metal Ions in Aqueous Solution

Trends and Exceptions in the Interaction of Hydroxamic Acid Derivatives of Common Di- and Tripeptides with Some 3d and 4d Metal Ions in Aqueous Solution

Metallophores and Trace Metal Biogeochemistry

Multiple roles of siderophores in free-living nitrogen-fixing bacteria

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