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Doydora SA, Baars O, Harrington JM, Duckworth OW. Salicylate coordination in metal-protochelin complexes. Biometals 2021; 35:87-98. [PMID: 34837588 DOI: 10.1007/s10534-021-00352-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 11/17/2021] [Indexed: 11/29/2022]
Abstract
Molybdenum (Mo) is an essential trace element for bacteria that is utilized in myriad metalloenzymes that directly couple to the biogeochemical cycling of nitrogen, sulfur, and carbon. In particular, Mo is found in the most common nitrogenase enzyme, and the scarcity and low bioavailability of Mo in soil may be a critical factor that contributes to the limitation of nitrogen fixation in forests and agroenvironments. To overcome this scarcity, microbes produce exudates that specifically chelate scarce metals, promoting their solubilization and uptake. Here, we have determined the structure and stability constants of Mo bound by protochelin, a siderophore produced by bacteria under Mo-depleted conditions. Spectrophotometric titration spectra indicated a coordination shift from a catecholate to salicylate binding mode for MoVI-protochelin (Mo-Proto) complexes at pH < 5. pKa values obtained from analysis of titrations were 4.8 ± 0.3 for MoVIO2H3Proto- and 3.3 ± 0.1 for MoVIO2H4Proto. The occurrence of negatively charged Mo-Proto complexes at pH 6 was also confirmed by mass spectrometry. K-edge Extended X-ray absorption fine structure spectroscopy confirmed the change in Mo coordination at low pH, and structural fitting provides insights into the physical architecture of complexes at neutral and acidic pH. These findings suggest that Mo can be chelated by protochelin across a wide environmental pH range, with a coordination shift occurring at pH < 5. This chelation and associated coordination shift may impact biological availability and mineral surface retention of Mo under acidic conditions.
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Affiliation(s)
- Sarah A Doydora
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC, 27695, USA
| | - Oliver Baars
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
| | - James M Harrington
- RTI International, 3040 East Cornwallis Road, Research Triangle Park, NC, 27709-2194, USA
| | - Owen W Duckworth
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC, 27695, USA.
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2
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Hofmann M, Heine T, Malik L, Hofmann S, Joffroy K, Senges CHR, Bandow JE, Tischler D. Screening for Microbial Metal-Chelating Siderophores for the Removal of Metal Ions from Solutions. Microorganisms 2021; 9:microorganisms9010111. [PMID: 33466508 PMCID: PMC7824959 DOI: 10.3390/microorganisms9010111] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 12/30/2020] [Indexed: 11/17/2022] Open
Abstract
To guarantee the supply of critical elements in the future, the development of new technologies is essential. Siderophores have high potential in the recovery and recycling of valuable metals due to their metal-chelating properties. Using the Chrome azurol S assay, 75 bacterial strains were screened to obtain a high-yield siderophore with the ability to complex valuable critical metal ions. The siderophore production of the four selected strains Nocardioides simplex 3E, Pseudomonas chlororaphis DSM 50083, Variovorax paradoxus EPS, and Rhodococcus erythropolis B7g was optimized, resulting in significantly increased siderophore production of N. simplex and R. erythropolis. Produced siderophore amounts and velocities were highly dependent on the carbon source. The genomes of N. simplex and P. chlororaphis were sequenced. Bioinformatical analyses revealed the occurrence of an achromobactin and a pyoverdine gene cluster in P. chlororaphis, a heterobactin and a requichelin gene cluster in R. erythropolis, and a desferrioxamine gene cluster in N. simplex. Finally, the results of the previous metal-binding screening were validated by a proof-of-concept development for the recovery of metal ions from aqueous solutions utilizing C18 columns functionalized with siderophores. We demonstrated the recovery of the critical metal ions V(III), Ga(III), and In(III) from mixed metal solutions with immobilized siderophores of N. simplex and R. erythropolis.
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Affiliation(s)
- Marika Hofmann
- Institute of Biosciences, TU Bergakademie Freiberg, 09599 Freiberg, Germany; (T.H.); (L.M.); (S.H.); (K.J.)
- Correspondence: (M.H.); (D.T.)
| | - Thomas Heine
- Institute of Biosciences, TU Bergakademie Freiberg, 09599 Freiberg, Germany; (T.H.); (L.M.); (S.H.); (K.J.)
| | - Luise Malik
- Institute of Biosciences, TU Bergakademie Freiberg, 09599 Freiberg, Germany; (T.H.); (L.M.); (S.H.); (K.J.)
| | - Sarah Hofmann
- Institute of Biosciences, TU Bergakademie Freiberg, 09599 Freiberg, Germany; (T.H.); (L.M.); (S.H.); (K.J.)
| | - Kristin Joffroy
- Institute of Biosciences, TU Bergakademie Freiberg, 09599 Freiberg, Germany; (T.H.); (L.M.); (S.H.); (K.J.)
| | - Christoph Helmut Rudi Senges
- Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, 44780 Bochum, Germany; (C.H.R.S.); (J.E.B.)
| | - Julia Elisabeth Bandow
- Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, 44780 Bochum, Germany; (C.H.R.S.); (J.E.B.)
| | - Dirk Tischler
- Microbial Biotechnology, Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, 44780 Bochum, Germany
- Correspondence: (M.H.); (D.T.)
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3
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Boyce JH, Dang B, Ary B, Edmondson Q, Craik CS, DeGrado WF, Seiple IB. Platform to Discover Protease-Activated Antibiotics and Application to Siderophore-Antibiotic Conjugates. J Am Chem Soc 2020; 142:21310-21321. [PMID: 33301681 DOI: 10.1021/jacs.0c06987] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Here we present a platform for discovery of protease-activated prodrugs and apply it to antibiotics that target Gram-negative bacteria. Because cleavable linkers for prodrugs had not been developed for bacterial proteases, we used substrate phage to discover substrates for proteases found in the bacterial periplasm. Rather than focusing on a single protease, we used a periplasmic extract of E. coli to find sequences with the greatest susceptibility to the endogenous mixture of periplasmic proteases. Using a fluorescence assay, candidate sequences were evaluated to identify substrates that release native amine-containing payloads. We next designed conjugates consisting of (1) an N-terminal siderophore to facilitate uptake, (2) a protease-cleavable linker, and (3) an amine-containing antibiotic. Using this strategy, we converted daptomycin-which by itself is active only against Gram-positive bacteria-into an antibiotic capable of targeting Gram-negative Acinetobacter species. We similarly demonstrated siderophore-facilitated delivery of oxazolidinone and macrolide antibiotics into a number of Gram-negative species. These results illustrate this platform's utility for development of protease-activated prodrugs, including Trojan horse antibiotics.
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Affiliation(s)
- Jonathan H Boyce
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158, United States.,Cardiovascular Research Institute, University of California, San Francisco, California 94158, United States
| | - Bobo Dang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China.,Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China.,Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Beatrice Ary
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158, United States
| | - Quinn Edmondson
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158, United States
| | - Charles S Craik
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158, United States
| | - William F DeGrado
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158, United States.,Cardiovascular Research Institute, University of California, San Francisco, California 94158, United States
| | - Ian B Seiple
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158, United States.,Cardiovascular Research Institute, University of California, San Francisco, California 94158, United States
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4
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Hofmann M, Retamal-Morales G, Tischler D. Metal binding ability of microbial natural metal chelators and potential applications. Nat Prod Rep 2020; 37:1262-1283. [DOI: 10.1039/c9np00058e] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Metallophores can chelate many different metal and metalloid ions next to iron, make them valuable for many applications.
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Affiliation(s)
- Marika Hofmann
- Institute of Biosciences
- Chemistry and Physics Faculty
- TU Bergakademie Freiberg
- 09599 Freiberg
- Germany
| | - Gerardo Retamal-Morales
- Laboratorio de Microbiología Básica y Aplicada
- Facultad de Química y Biología
- Universidad de Santiago de Chile
- Santiago
- Chile
| | - Dirk Tischler
- Microbial Biotechnology
- Ruhr-Universität Bochum
- 44780 Bochum
- Germany
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5
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Baars O, Morel FMM, Zhang X. The purple non-sulfur bacterium Rhodopseudomonas palustris produces novel petrobactin-related siderophores under aerobic and anaerobic conditions. Environ Microbiol 2018; 20:1667-1676. [PMID: 29473283 DOI: 10.1111/1462-2920.14078] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 01/20/2018] [Accepted: 02/17/2018] [Indexed: 11/28/2022]
Abstract
Many bacteria produce siderophores to bind and take up Fe(III), an essential trace metal with extremely low solubility in oxygenated environments at circumneutral pH. The purple non-sulfur bacterium Rhodopseudomonas palustris str. CGA009 is a metabolically versatile model organism with high iron requirements that is able to grow under aerobic and anaerobic conditions. Siderophore biosynthesis has been predicted by genomic analysis, however, siderophore structures were not identified. Here, we elucidate the structure of two novel siderophores from R. palustris: rhodopetrobactin A and B. Rhodopetrobactins are structural analogues of the known siderophore petrobactin in which the Fe chelating moieties are conserved, including two 3,4-dihydroxybenzoate and a citrate substructure. In the place of two spermidine linker groups in petrobactin, rhodopetrobactins contain two 4,4'-diaminodibutylamine groups of which one or both are acetylated at the central amine. We analyse siderophore production under different growth modes and show that rhodopetrobactins are produced in response to Fe limitation under aerobic as well as under anaerobic conditions. Evaluation of the chemical characteristics of rhodopetrobactins indicates that they are well suited to support Fe acquisition under variable oxygen and light conditions.
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Affiliation(s)
- Oliver Baars
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
| | - François M M Morel
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
| | - Xinning Zhang
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
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6
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McRose DL, Baars O, Morel FMM, Kraepiel AML. Siderophore production in
Azotobacter vinelandii
in response to Fe‐, Mo‐ and V‐limitation. Environ Microbiol 2017; 19:3595-3605. [DOI: 10.1111/1462-2920.13857] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 07/08/2017] [Indexed: 11/26/2022]
Affiliation(s)
- Darcy L. McRose
- Department of GeosciencesPrinceton UniversityPrinceton NJ 08544 USA
| | - Oliver Baars
- Department of GeosciencesPrinceton UniversityPrinceton NJ 08544 USA
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7
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Folkman SJ, Kirner JT, Finke RG. Cobalt Polyoxometalate Co4V2W18O6810–: A Critical Investigation of Its Synthesis, Purity, and Observed 51V Quadrupolar NMR. Inorg Chem 2016; 55:5343-55. [DOI: 10.1021/acs.inorgchem.6b00324] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Scott J. Folkman
- Chemistry
Department, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Joel T. Kirner
- Chemistry
Department, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Richard G. Finke
- Chemistry
Department, Colorado State University, Fort Collins, Colorado 80523, United States
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8
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Noumsi CJ, Pourhassan N, Darnajoux R, Deicke M, Wichard T, Burrus V, Bellenger JP. Effect of organic matter on nitrogenase metal cofactors homeostasis in Azotobacter vinelandii under diazotrophic conditions. ENVIRONMENTAL MICROBIOLOGY REPORTS 2016; 8:76-84. [PMID: 26549632 DOI: 10.1111/1758-2229.12353] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 10/30/2015] [Accepted: 10/30/2015] [Indexed: 06/05/2023]
Abstract
Biological nitrogen fixation can be catalysed by three isozymes of nitrogenase: molybdenum (Mo)-nitrogenase, vanadium (V)-nitrogenase and iron-only (Fe)-nitrogenase. The activity of these isozymes strongly depends on their metal cofactors, molybdenum, vanadium and iron, and their bioavailability in ecosystems. Here, we show how metal bioavailability can be affected by the presence of tannic acid (organic matter), and the subsequent consequences on diazotrophic growth of the soil bacterium Azotobacter vinelandii. In the presence of tannic acids, A. vinelandii produces a higher amount of metallophores, which coincides with an active, regulated and concomitant acquisition of molybdenum and vanadium under cellular conditions that are usually considered not molybdenum limiting. The associated nitrogenase genes exhibit decreased nifD expression and increased vnfD expression. Thus, in limiting bioavailable metal conditions, A. vinelandii takes advantage of its nitrogenase diversity to ensure optimal diazotrophic growth.
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Affiliation(s)
- Christelle Jouogo Noumsi
- Département de Chimie, Faculté des sciences, Université de Sherbrooke, 2500 boul. de l'université, Sherbrooke, Québec, J1K 2R1, Canada
- Laboratory of Bacterial Molecular Genetics, Département de biologie, Faculté des sciences, Université de Sherbrooke, 2500 boul. de l'université, Sherbrooke, Québec, J1K 2R1, Canada
| | - Nina Pourhassan
- Département de Chimie, Faculté des sciences, Université de Sherbrooke, 2500 boul. de l'université, Sherbrooke, Québec, J1K 2R1, Canada
| | - Romain Darnajoux
- Département de Chimie, Faculté des sciences, Université de Sherbrooke, 2500 boul. de l'université, Sherbrooke, Québec, J1K 2R1, Canada
| | - Michael Deicke
- Institute for Inorganic and Analytical Chemistry, Jena School for Microbial Communication, Friedrich Schiller University Jena, Jena, Germany
| | - Thomas Wichard
- Institute for Inorganic and Analytical Chemistry, Jena School for Microbial Communication, Friedrich Schiller University Jena, Jena, Germany
| | - Vincent Burrus
- Laboratory of Bacterial Molecular Genetics, Département de biologie, Faculté des sciences, Université de Sherbrooke, 2500 boul. de l'université, Sherbrooke, Québec, J1K 2R1, Canada
| | - Jean-Philippe Bellenger
- Département de Chimie, Faculté des sciences, Université de Sherbrooke, 2500 boul. de l'université, Sherbrooke, Québec, J1K 2R1, Canada
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9
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10
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Baars O, Morel FMM, Perlman DH. ChelomEx: Isotope-assisted discovery of metal chelates in complex media using high-resolution LC-MS. Anal Chem 2014; 86:11298-305. [PMID: 25333600 DOI: 10.1021/ac503000e] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chelating agents can control the speciation and reactivity of trace metals in biological, environmental, and laboratory-derived media. A large number of trace metals (including Fe, Cu, Zn, Hg, and others) show characteristic isotopic fingerprints that can be exploited for the discovery of known and unknown organic metal complexes and related chelating ligands in very complex sample matrices using high-resolution liquid chromatography mass spectrometry (LC-MS). However, there is currently no free open-source software available for this purpose. We present a novel software tool, ChelomEx, which identifies isotope pattern-matched chromatographic features associated with metal complexes along with free ligands and other related adducts in high-resolution LC-MS data. High sensitivity and exclusion of false positives are achieved by evaluation of the chromatographic coherence of the isotope pattern within chromatographic features, which we demonstrate through the analysis of bacterial culture media. A built-in graphical user interface and compound library aid in identification and efficient evaluation of results. ChelomEx is implemented in MatLab. The source code, binaries for MS Windows and MAC OS X as well as test LC-MS data are available for download at SourceForge ( http://sourceforge.net/projects/chelomex ).
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Affiliation(s)
- Oliver Baars
- Department of Geosciences, Princeton University , Princeton, New Jersey 08544, United States
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11
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Levina A, McLeod AI, Lay PA. Vanadium Speciation by XANES Spectroscopy: A Three-Dimensional Approach. Chemistry 2014; 20:12056-60. [DOI: 10.1002/chem.201403993] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Indexed: 11/09/2022]
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12
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Deicke M, Mohr JF, Bellenger JP, Wichard T. Metallophore mapping in complex matrices by metal isotope coded profiling of organic ligands. Analyst 2014; 139:6096-9. [DOI: 10.1039/c4an01461h] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Metal isotope coded profiling (MICP) utilizes stable metal isotope pairs creating unique isotopic signatures used for fast identification of metallophores, metal ion buffers or sequestering agents.
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Affiliation(s)
- Michael Deicke
- Friedrich Schiller University Jena
- Institute for Inorganic and Analytical Chemistry
- 07743 Jena, Germany
| | - Jan Frieder Mohr
- Friedrich Schiller University Jena
- Institute for Inorganic and Analytical Chemistry
- 07743 Jena, Germany
| | | | - Thomas Wichard
- Friedrich Schiller University Jena
- Institute for Inorganic and Analytical Chemistry
- 07743 Jena, Germany
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13
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Baco E, Hoegy F, Schalk IJ, Mislin GLA. Diphenyl-benzo[1,3]dioxole-4-carboxylic acid pentafluorophenyl ester: a convenient catechol precursor in the synthesis of siderophore vectors suitable for antibiotic Trojan horse strategies. Org Biomol Chem 2014; 12:749-57. [DOI: 10.1039/c3ob41990h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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14
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Deicke M, Bellenger JP, Wichard T. Direct quantification of bacterial molybdenum and iron metallophores with ultra-high-performance liquid chromatography coupled to time-of-flight mass spectrometry. J Chromatogr A 2013; 1298:50-60. [DOI: 10.1016/j.chroma.2013.05.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Revised: 04/30/2013] [Accepted: 05/02/2013] [Indexed: 10/26/2022]
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15
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Allard P, Darnajoux R, Phalyvong K, Bellenger JP. Effects of tungsten and titanium oxide nanoparticles on the diazotrophic growth and metals acquisition by Azotobacter vinelandii under molybdenum limiting condition. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:2061-2068. [PMID: 23339336 DOI: 10.1021/es304544k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The acquisition of essential metals, such as the metal cofactors (molybdenum (Mo) and iron (Fe)) of the nitrogenase, the enzyme responsible for the reduction of dinitrogen (N(2)) to ammonium, is critical to N(2) fixing bacteria in soil. The release of metal nanoparticles (MNPs) to the environment could be detrimental to N(2) fixing bacteria by introducing a new source of toxic metals and by interfering with the acquisition of essential metals such as Mo. Since Mo has been reported to limit nonsymbiotic N(2) fixation in many ecosystems from tropical to cold temperate, this question is particularly acute in the context of Mo limitation. Using a combination of microbiology and analytical chemistry techniques, we have evaluated the effect of titanium (Ti) and tungsten (W) oxide nanoparticles on the diazotrophic growth and metals acquisition in pure culture of the ubiquitous N(2) fixing bacterium Azotobacter vinelandii under Mo replete and Mo limiting conditions. We report that under our conditions (≤10 mg·L(-1)) TiO(2) NPs have no effects on the diazotrophic growth of A. vinelandii while WO(3) NPs are highly detrimental to the growth especially under Mo limiting conditions. Our results show that the toxicity of WO(3) NPs to A. vinelandii is due to an interference with the catechol-metalophores assisted uptake of Mo.
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Affiliation(s)
- Patrick Allard
- Département de Chimie, Université de Sherbrooke, 2500 Boul. de l'Université, Sherbrooke, Québec J1K 2R1, Canada
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16
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Harrington JM, Bargar JR, Jarzecki AA, Roberts JG, Sombers LA, Duckworth OW. Trace metal complexation by the triscatecholate siderophore protochelin: structure and stability. Biometals 2011; 25:393-412. [PMID: 22187125 DOI: 10.1007/s10534-011-9513-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 12/01/2011] [Indexed: 11/29/2022]
Abstract
Although siderophores are generally viewed as biological iron uptake agents, recent evidence has shown that they may play significant roles in the biogeochemical cycling and biological uptake of other metals. One such siderophore that is produced by A. vinelandii is the triscatecholate protochelin. In this study, we probe the solution chemistry of protochelin and its complexes with environmentally relevant trace metals to better understand its effect on metal uptake and cycling. Protochelin exhibits low solubility below pH 7.5 and degrades gradually in solution. Electrochemical measurements of protochelin and metal-protochelin complexes reveal a ligand half-wave potential of 200 mV. The Fe(III)Proto(3-) complex exhibits a salicylate shift in coordination mode at circumneutral to acidic pH. Coordination of Mn(II) by protochelin above pH 8.0 promotes gradual air oxidation of the metal center to Mn(III), which accelerates at higher pH values. The Mn(III)Proto(3-) complex was found to have a stability constant of log β(110) = 41.6. Structural parameters derived from spectroscopic measurements and quantum mechanical calculations provide insights into the stability of the Fe(III)Proto(3-), Fe(III)H(3)Proto, and Mn(III)Proto(3-) complexes. Complexation of Co(II) by protochelin results in redox cycling of Co, accompanied by accelerated degradation of the ligand at all solution pH values. These results are discussed in terms of the role of catecholate siderophores in environmental trace metal cycling and intracellular metal release.
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Affiliation(s)
- James M Harrington
- Soil Science Department, North Carolina State University, Raleigh, NC 27695-7619, USA
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17
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Das D, Sarkar B, Kumbhakar D, Mondal TK, Mobin SM, Fiedler J, Urbanos FA, Jiménez-Aparicio R, Kaim W, Lahiri GK. Bis(acetylacetonato)ruthenium Complexes of Noninnocent 1,2-Dioxolene Ligands: Qualitatively Different Bonding in Relation to Monoimino and Diimino Analogues. Chemistry 2011; 17:11030-40. [DOI: 10.1002/chem.201101009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2011] [Indexed: 11/11/2022]
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18
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Yoneyama F, Yamamoto M, Hashimoto W, Murata K. Azotobacter vinelandii gene clusters for two types of peptidic and catechol siderophores produced in response to molybdenum. J Appl Microbiol 2011; 111:932-8. [PMID: 21794033 DOI: 10.1111/j.1365-2672.2011.05109.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
AIM To characterize the complementary production of two types of siderophores in Azotobacter vinelandii. METHODS AND RESULTS In an iron-insufficient environment, nitrogen-fixing A. vinelandii produces peptidic (azotobactin) and catechol siderophores for iron uptake to be used as a nitrogenase cofactor. Molybdenum, another nitrogenase cofactor, was also found to affect the production level of siderophores. Wild-type cells excreted azotobactin into molybdenum-supplemented and iron-insufficient medium, although catechol siderophores predominate in molybdenum-free environments. Two gene clusters were identified to be involved in the production of azotobactin and catechol siderophores through gene annotation and disruption. Azotobactin-deficient mutant cells produced catechol siderophores under the molybdenum-supplemented and iron-insufficient conditions, whereas catechol siderophore-deficient mutant cells extracellularly secreted excess azotobactin under iron-deficient condition independent of the concentration of molybdenum. This evidence suggests that a complementary siderophore production system exists in A. vinelandii. CONCLUSIONS Molybdenum was found to regulate the production level of two types of siderophores. Azotobacter vinelandii cells are equipped with a complementary production system for nitrogen fixation in response to a limited quantity of metals. SIGNIFICANCE AND IMPACT OF THE STUDY This is the first study identifying A. vinelandii gene clusters for the biosynthesis of two types of siderophores and clarifying the relationship between them.
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Affiliation(s)
- F Yoneyama
- Laboratory of Basic and Applied Molecular Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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19
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20
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21
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Bellenger JP, Wichard T, Xu Y, Kraepiel AML. Essential metals for nitrogen fixation in a free-living N₂-fixing bacterium: chelation, homeostasis and high use efficiency. Environ Microbiol 2011; 13:1395-411. [PMID: 21392197 DOI: 10.1111/j.1462-2920.2011.02440.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Biological nitrogen fixation, the main source of new nitrogen to the Earth's ecosystems, is catalysed by the enzyme nitrogenase. There are three nitrogenase isoenzymes: the Mo-nitrogenase, the V-nitrogenase and the Fe-only nitrogenase. All three types require iron, and two of them also require Mo or V. Metal bioavailability has been shown to limit nitrogen fixation in natural and managed ecosystems. Here, we report the results of a study on the metal (Mo, V, Fe) requirements of Azotobacter vinelandii, a common model soil diazotroph. In the growth medium of A. vinelandii, metals are bound to strong complexing agents (metallophores) excreted by the bacterium. The uptake rates of the metallophore complexes are regulated to meet the bacterial metal requirement for diazotrophy. Under metal-replete conditions Mo, but not V or Fe, is stored intracellularly. Under conditions of metal limitation, intracellular metals are used with remarkable efficiency, with essentially all the cellular Mo and V allocated to the nitrogenase enzymes. While the Mo-nitrogenase, which is the most efficient, is used preferentially, all three nitrogenases contribute to N₂ fixation in the same culture under metal limitation. We conclude that A. vinelandii is well adapted to fix nitrogen in metal-limited soil environments.
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Affiliation(s)
- J-P Bellenger
- Department of Geosciences, PEI, Guyot Hall, Princeton University, Princeton, NJ 08544, USA.
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Kojima T, Hirasa N, Noguchi D, Ishizuka T, Miyazaki S, Shiota Y, Yoshizawa K, Fukuzumi S. Synthesis and Characterization of Ruthenium(II)−Pyridylamine Complexes with Catechol Pendants as Metal Binding Sites. Inorg Chem 2010; 49:3737-45. [DOI: 10.1021/ic902070q] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Takahiko Kojima
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571
| | - Norihisa Hirasa
- Department of Material and Life Science, Graduate School of Engineering, Osaka University and SORST (JST), 2-1 Yamada-oka, Suita, Osaka 565-0871
| | | | - Tomoya Ishizuka
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571
| | - Soushi Miyazaki
- Department of Material and Life Science, Graduate School of Engineering, Osaka University and SORST (JST), 2-1 Yamada-oka, Suita, Osaka 565-0871
| | | | | | - Shunichi Fukuzumi
- Department of Material and Life Science, Graduate School of Engineering, Osaka University and SORST (JST), 2-1 Yamada-oka, Suita, Osaka 565-0871
- Department of Bioinspired Science, Ewha Womans University, Seoul, 120-750, Korea
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Wichard T, Bellenger JP, Morel FMM, Kraepiel AML. Role of the siderophore azotobactin in the bacterial acquisition of nitrogenase metal cofactors. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:7218-24. [PMID: 19848125 DOI: 10.1021/es8037214] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Fixation of dinitrogen by soil bacteria is catalyzed by the enzyme nitrogenase which requires iron, molybdenum, and/or vanadium as metal cofactors. Under conditions of iron deficiency, the ubiquitous N2-fixing bacterium Azotobacter vinelandii produces azotobactin, a fluorescent pyoverdine-like compound which serves as a siderophore. Azotobatin's hydroxamate, catechol, and alpha-hydroxy-acid moieties endow it with a very high affinity for Fe(III), and the Fe complex is taken up by the bacterium. Here we show that azotobactin also serves for the uptake of Mo and V. Azotobactin forms strong complexes with molybdate and vanadate and the complexes are taken up by regulated transport systems. The kinetics of complexation of molybdate and vanadate by azotobactin are faster than the complexation of Fe(III), which is either precipitated or bound to strong complexing agents. As a result of this kinetic advantage, the Mo and V complexes of azotobactin form despite the higher affinity of the compound for Fe, which is present in large excess in the environment. The results obtained here for azotobactin and previous data for the bis- and tris-catechols produced by A. vinelandii show that those "siderophores" are really "metallophores" that promote the bacterial acquisition of Mo and V in addition to Fe.
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Affiliation(s)
- Thomas Wichard
- Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Lessingstr. 8, 07743 Jena, Germany.
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Duhme‐Klair A. From Siderophores and Self‐Assembly to Luminescent Sensors: The Binding of Molybdenum by Catecholamides. Eur J Inorg Chem 2009. [DOI: 10.1002/ejic.200900416] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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25
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Kraepiel AML, Bellenger JP, Wichard T, Morel FMM. Multiple roles of siderophores in free-living nitrogen-fixing bacteria. Biometals 2009; 22:573-81. [DOI: 10.1007/s10534-009-9222-7] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 02/11/2009] [Indexed: 10/21/2022]
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Hazari SK, Kopf J, Palit D, Rakshit S, Rehder D. Oxidovanadium(IV) complexes containing ligands derived from dithiocarbazates – Models for the interaction of VO2+ with thiofunctional ligands. Inorganica Chim Acta 2009. [DOI: 10.1016/j.ica.2008.06.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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27
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Crumbliss AL, Harrington JM. Iron sequestration by small molecules: Thermodynamic and kinetic studies of natural siderophores and synthetic model compounds. ADVANCES IN INORGANIC CHEMISTRY 2009. [DOI: 10.1016/s0898-8838(09)00204-9] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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28
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Wichard T, Bellenger JP, Loison A, Kraepiel AML. Catechol siderophores control tungsten uptake and toxicity in the nitrogen-fixing bacterium Azotobacter vinelandii. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:2408-2413. [PMID: 18504973 DOI: 10.1021/es702651f] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Molybdenum (Mo) and tungsten (W), which have similar chemistry, are present at roughly the same concentration in the earth's continental crust, and both are present in oxic systems as oxoanions, molybdate and tungstate. Molybdenum is a cofactor in the molybdenum-nitrogenase enzyme and is thus an important micronutrient for N2-fixing bacteria such as Azotobacter vinelandii (A. vinelandii). Tungsten is known to be toxic to N2-fixing bacteria, partly by substituting for Mo in nitrogenase. We showthatthe catechol siderophores produced by A. vinelandii, in addition to being essential for iron acquisition, modulate the relative uptake of Mo and W. These catechol siderophores (particularly protochelin), whose concentrations in the growth medium increase sharply at high W, complex all the tungstate along with molybdate and some of the iron. The molybdenum-catechol complex is taken up much more rapidly than the W complex, allowing A. vinelandii to satisfy its Mo requirement and avoid W toxicity. Mutants deficient in the production of catechol siderophores are more sensitive to tungstate and have higher cellular W quotas than the wild type. The binding of metals by excreted catechol siderophores allows A. vinelandii to discriminate in its uptake of essential metals, such as Fe and Mo, over that of toxic metals, such as W, and to sustain high growth rates under adverse environmental conditions.
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Affiliation(s)
- Thomas Wichard
- Department of Geosciences, Princeton Environmental Institute, Guyot Hall, Princeton University, Princeton, New Jersey 08544, USA
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Bellenger JP, Wichard T, Kraepiel AML. Vanadium requirements and uptake kinetics in the dinitrogen-fixing bacterium Azotobacter vinelandii. Appl Environ Microbiol 2008; 74:1478-84. [PMID: 18192412 PMCID: PMC2258613 DOI: 10.1128/aem.02236-07] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 01/01/2008] [Indexed: 11/20/2022] Open
Abstract
Vanadium is a cofactor in the alternative V-nitrogenase that is expressed by some N(2)-fixing bacteria when Mo is not available. We investigated the V requirements, the kinetics of V uptake, and the production of catechol compounds across a range of concentrations of vanadium in diazotrophic cultures of the soil bacterium Azotobacter vinelandii. In strain CA11.70, a mutant that expresses only the V-nitrogenase, V concentrations in the medium between 10(-8) and 10(-6) M sustain maximum growth rates; they are limiting below this range and toxic above. A. vinelandii excretes in its growth medium micromolar concentrations of the catechol siderophores azotochelin and protochelin, which bind the vanadate oxoanion. The production of catechols increases when V concentrations become toxic. Short-term uptake experiments with the radioactive isotope (49)V show that bacteria take up the V-catechol complexes through a regulated transport system(s), which shuts down at high V concentrations. The modulation of the excretion of catechols and of the uptake of the V-catechol complexes allows A. vinelandii to precisely manage its V homeostasis over a range of V concentrations, from limiting to toxic.
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Affiliation(s)
- J P Bellenger
- Chemistry Department, Guyot Hall, Princeton University, Princeton, NJ 08544, USA
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Rehder D. Is vanadium a more versatile target in the activity of primordial life forms than hitherto anticipated? Org Biomol Chem 2008; 6:957-64. [PMID: 18327316 DOI: 10.1039/b717565p] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The two predominant forms of vanadium occurring in the geo-, aqua- and biosphere, soluble vanadate(V) and insoluble oxovanadium(IV) (vanadyl), are subject to bacterial activity and transformation. Bacteria belonging to genera such as Shewanella, Pseudomonas and Geobacter can use vanadate as a primary electron acceptor in dissimilation or respiration, an important issue in the context of biomineralisation and soil detoxification. Azotobacter, which can employ vanadium as an essential element in nitrogen fixation, secretes a vanadophore which enables the uptake of vanadium(V). Siderophores secreted by other bacteria competitively (to ferric iron) take up vanadyl and thus interfere with iron supply, resulting in bacteriostasis. The halo-alkaliphilic Thioalkalivibrio nitratireducens possibly uses vanadium as a constituent of an alternative, molybdopterin-free nitrate reductase. Marine macro-algae can generate a variety of halogenated organic compounds by use of vanadate-dependent haloperoxidases, and a molecular vanadium compound, amavadin, from Amanita mushrooms has turned out to be an efficient catalyst in oxidation reactions. The present account is a focused and critical review of the current knowledge of the interplay of bacteria and other primitive forms of life (cyanobacteria, algae, fungi and lichens) with vanadium, with the aim to provide perspectives for applications and further investigations.
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Affiliation(s)
- Dieter Rehder
- Department of Chemistry, University of Hamburg, 20146 Hamburg, Germany.
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