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Lai J, Wang B, Petrik M, Beziere N, Hammoud DA. Radiotracer Development for Fungal-Specific Imaging: Past, Present, and Future. J Infect Dis 2023; 228:S259-S269. [PMID: 37788500 PMCID: PMC10547453 DOI: 10.1093/infdis/jiad067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023] Open
Abstract
Invasive fungal infections have become a major challenge for public health, mainly due to the growing numbers of immunocompromised patients, with high morbidity and mortality. Currently, conventional imaging modalities such as computed tomography and magnetic resonance imaging contribute largely to the noninvasive diagnosis and treatment evaluation of those infections. These techniques, however, often fall short when a fast, noninvasive and specific diagnosis of fungal infection is necessary. Molecular imaging, especially using nuclear medicine-based techniques, aims to develop fungal-specific radiotracers that can be tested in preclinical models and eventually translated to human applications. In the last few decades, multiple radioligands have been developed and tested as potential fungal-specific tracers. These include radiolabeled peptides, antifungal drugs, siderophores, fungal-specific antibodies, and sugars. In this review, we provide an overview of the pros and cons of the available radiotracers. We also address the future prospects of fungal-specific imaging.
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Affiliation(s)
- Jianhao Lai
- Center for Infectious Disease Imaging, Radiology, and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Benjamin Wang
- Center for Infectious Disease Imaging, Radiology, and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Milos Petrik
- Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacky University Olomouc, Olomouc, Czech Republic
- Czech Advanced Technology and Research Institute, Palacky University Olomouc, Olomouc, Czech Republic
| | - Nicolas Beziere
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Dima A Hammoud
- Center for Infectious Disease Imaging, Radiology, and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
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Mular A, Shanzer A, Kozłowski H, Hubmann I, Misslinger M, Krzywik J, Decristoforo C, Gumienna-Kontecka E. Cyclic Analogs of Desferrioxamine E Siderophore for 68Ga Nuclear Imaging: Coordination Chemistry and Biological Activity in Staphylococcus aureus. Inorg Chem 2021; 60:17846-17857. [PMID: 34783539 PMCID: PMC8653149 DOI: 10.1021/acs.inorgchem.1c02453] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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As multidrug-resistant
bacteria are an emerging problem and threat
to humanity, novel strategies for treatment and diagnostics are actively
sought. We aim to utilize siderophores, iron-specific strong chelating
agents produced by microbes, as gallium ion carriers for diagnosis,
applying that Fe(III) can be successfully replaced by Ga(III) without
losing biological properties of the investigated complex, which allows
molecular imaging by positron emission tomography (PET). Here, we
report synthesis, full solution chemistry, thermodynamic characterization,
and the preliminary biological evaluation of biomimetic derivatives
(FOX) of desferrioxamine E (FOXE) siderophore, radiolabeled with 68Ga for possible applications in PET imaging of S.
aureus. From a series of six biomimetic analogs, which differ
from FOXE with cycle length and position of hydroxamic and amide groups,
the highest Fe(III) and Ga(III) stability was determined for the most
FOXE alike compounds–FOX 2-4 and FOX 2-5; we have also established
the stability constant of the Ga-FOXE complex. For this purpose, spectroscopic
and potentiometric titrations, together with the Fe(III)–Ga(III)
competition method, were used. [68Ga]Ga-FOXE derivatives
uptake and microbial growth promotion studies conducted on S. aureus were efficient for compounds with a larger cavity,
i.e., FOX 2-5, 2-6, and 3-5. Even though showing low uptake values,
Fe-FOX 2-4 seems to be also a good Fe-source to support the growth
of S. aureus. Overall, proposed derivatives may hold
potential as inert and stable carrier agents for radioactive Ga(III)
ions for diagnostic medical applications or interesting starting compounds
for further modifications. In this work,
the authors have investigated a set of novel
ferrioxamine E analogs as potential Ga-68 chelators and tools for
infection imaging.
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Affiliation(s)
- Andrzej Mular
- Faculty of Chemistry, University of Wrocław, 50-383 Wrocław, Poland
| | - Abraham Shanzer
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Henryk Kozłowski
- Faculty of Chemistry, University of Wrocław, 50-383 Wrocław, Poland.,Department of Health Sciences, University of Opole, 45-060 Opole, Poland
| | - Isabella Hubmann
- Department of Nuclear Medicine, Medical University Innsbruck, A-6020 Innsbruck, Austria
| | - Matthias Misslinger
- Institute of Molecular Biology, Medical University Innsbruck, A-6020 Innsbruck, Austria
| | - Julia Krzywik
- TriMen Chemicals, Piłsudskiego 141, 92-318 Łódź, Poland
| | - Clemens Decristoforo
- Department of Nuclear Medicine, Medical University Innsbruck, A-6020 Innsbruck, Austria
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3
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Chan KH, Groves JT. Concise Modular Synthesis and NMR Structural Determination of Gallium Mycobactin T. J Org Chem 2021; 86:15453-15468. [PMID: 34699221 DOI: 10.1021/acs.joc.1c01966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A modular synthesis of mycobactin T and its N-acetyl analogue is reported in a route that facilitates permutation of the lipid tails. A key feature is the generation of N(α)-Cbz-N(ε)-benzyloxy-N(ε)-Boc-lysine (A4) with methyl(trifluoromethyl)dioxirane in 59% yield. Selective hydroxamate N-acylation was achieved with acyl fluorides, enabling installation of lipids tails in the final step. O-Benzyl-dehydrocobactin T (B4) was prepared by modifying a known five-step sequence with an overall yield of 49%. 2-Hydroxyphenyl-4-carboxyloxazoline (C3) was prepared from 2-hydroxybenzoic acid and l-serine methyl ester in three steps with an overall yield of 55%. Ester coupling of A4 and B4 with EDCI afforded MbI-1 in 73% yield. Catalytic hydrogenation with Pd/BaSO4 and 50 psi of H2 simultaneously effected alkene reduction and debenzylation to afford MbI-2 in 96% yield. Fragment C3 was converted into acyl fluoride C4, which coupled with MbI-2 to afford MbI-3 in 51% yield. Finally, Boc-removal with HCl/EtOAc and treatment of the resultant hydroxylamine with stearyl fluoride furnished mycobactin T in 65% yield. Overall, the yield is 4% over 14 steps. The gallium mycobactin T-N-acetyl derivative (GaMbT-NAc) structure was determined by 1H NMR. The structure shows an octahedral Ga and two internal hydrogen bonds between peptidic N-Hs and two of the oxygen atoms coordinating Ga.
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Affiliation(s)
- Kiat Hwa Chan
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.,Division of Science, Yale-NUS College, 16 College Avenue West, Singapore 138527, Singapore
| | - John T Groves
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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4
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Misslinger M, Petrik M, Pfister J, Hubmann I, Bendova K, Decristoforo C, Haas H. Desferrioxamine B-Mediated Pre-Clinical In Vivo Imaging of Infection by the Mold Fungus Aspergillus fumigatus. J Fungi (Basel) 2021; 7:734. [PMID: 34575772 PMCID: PMC8472378 DOI: 10.3390/jof7090734] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/26/2021] [Accepted: 09/04/2021] [Indexed: 12/16/2022] Open
Abstract
Fungal infections are a serious threat, especially for immunocompromised patients. Early and reliable diagnosis is crucial to treat such infections. The bacterially produced siderophore desferrioxamine B (DFO-B) is utilized by a variety of microorganisms for iron acquisition, while mammalian cells lack the uptake of DFO-B chelates. DFO-B is clinically approved for a variety of long-term chelation therapies. Recently, DFO-B-complexed gallium-68 ([68Ga]Ga-DFO-B) was shown to enable molecular imaging of bacterial infections by positron emission tomography (PET). Here, we demonstrate that [68Ga]Ga-DFO-B can also be used for the preclinical molecular imaging of pulmonary infection caused by the fungal pathogen Aspergillus fumigatus in a rat aspergillosis model. Moreover, by combining in vitro uptake studies and the chemical modification of DFO-B, we show that the cellular transport efficacy of ferrioxamine-type siderophores is impacted by the charge of the molecule and, consequently, the environmental pH. The chemical derivatization has potential implications for its diagnostic use and characterizes transport features of ferrioxamine-type siderophores.
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Affiliation(s)
- Matthias Misslinger
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| | - Milos Petrik
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 77900 Olomouc, Czech Republic; (M.P.); (K.B.)
| | - Joachim Pfister
- Department of Nuclear Medicine, Medical University of Innsbruck, 6020 Innsbruck, Austria; (J.P.); (I.H.)
| | - Isabella Hubmann
- Department of Nuclear Medicine, Medical University of Innsbruck, 6020 Innsbruck, Austria; (J.P.); (I.H.)
| | - Katerina Bendova
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 77900 Olomouc, Czech Republic; (M.P.); (K.B.)
| | - Clemens Decristoforo
- Department of Nuclear Medicine, Medical University of Innsbruck, 6020 Innsbruck, Austria; (J.P.); (I.H.)
| | - Hubertus Haas
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria;
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5
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Characterization of two siderophores produced by Bacillus megaterium: A preliminary investigation into their potential as therapeutic agents. Biochim Biophys Acta Gen Subj 2020; 1864:129670. [DOI: 10.1016/j.bbagen.2020.129670] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/06/2020] [Accepted: 06/12/2020] [Indexed: 02/06/2023]
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6
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Petrik M, Umlaufova E, Raclavsky V, Palyzova A, Havlicek V, Pfister J, Mair C, Novy Z, Popper M, Hajduch M, Decristoforo C. 68Ga-labelled desferrioxamine-B for bacterial infection imaging. Eur J Nucl Med Mol Imaging 2020; 48:372-382. [PMID: 32734456 PMCID: PMC7835195 DOI: 10.1007/s00259-020-04948-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 06/29/2020] [Indexed: 12/21/2022]
Abstract
Purpose With the increase of especially hospital-acquired infections, timely and accurate diagnosis of bacterial infections is crucial for effective patient care. Molecular imaging has the potential for specific and sensitive detection of infections. Siderophores are iron-specific chelators recognized by specific bacterial transporters, representing one of few fundamental differences between bacterial and mammalian cells. Replacing iron by gallium-68 without loss of bioactivity is possible allowing molecular imaging by positron emission tomography (PET). Here, we report on the preclinical evaluation of the clinically used siderophore, desferrioxamine-B (Desferal®, DFO-B), radiolabelled with 68Ga for imaging of bacterial infections. Methods In vitro characterization of [68Ga]Ga-DFO-B included partition coefficient, protein binding and stability determination. Specific uptake of [68Ga]Ga-DFO-B was tested in vitro in different microbial cultures. In vivo biodistribution was studied in healthy mice and dosimetric estimation for human setting performed. PET/CT imaging was carried out in animal infection models, representing the most common pathogens. Results DFO-B was labelled with 68Ga with high radiochemical purity and displayed hydrophilic properties, low protein binding and high stability in human serum and PBS. The high in vitro uptake of [68Ga]Ga-DFO-B in selected strains of Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus agalactiae could be blocked with an excess of iron-DFO-B. [68Ga]Ga-DFO-B showed rapid renal excretion and minimal retention in blood and other organs in healthy mice. Estimated human absorbed dose was 0.02 mSv/MBq. PET/CT images of animal infection models displayed high and specific accumulation of [68Ga]Ga-DFO-B in both P. aeruginosa and S. aureus infections with excellent image contrast. No uptake was found in sterile inflammation, heat-inactivated P. aeruginosa or S. aureus and Escherichia coli lacking DFO-B transporters. Conclusion DFO-B can be easily radiolabelled with 68Ga and displayed suitable in vitro characteristics and excellent pharmacokinetics in mice. The high and specific uptake of [68Ga]Ga-DFO-B by P. aeruginosa and S. aureus was confirmed both in vitro and in vivo, proving the potential of [68Ga]Ga-DFO-B for specific imaging of bacterial infections. As DFO-B is used in clinic for many years and the estimated radiation dose is lower than for other 68Ga-labelled radiopharmaceuticals, we believe that [68Ga]Ga-DFO-B has a great potential for clinical translation. Electronic supplementary material The online version of this article (10.1007/s00259-020-04948-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Milos Petrik
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, CZ-77900, Olomouc, Czech Republic.
| | - Eva Umlaufova
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, CZ-77900, Olomouc, Czech Republic
| | - Vladislav Raclavsky
- Department of Microbiology, Faculty of Medicine and Dentistry, Palacky University and University Hospital, Olomouc, Czech Republic
| | - Andrea Palyzova
- Institute of Microbiology of the Czech Academy of Sciences v.v.i., Prague, Czech Republic
| | - Vladimir Havlicek
- Institute of Microbiology of the Czech Academy of Sciences v.v.i., Prague, Czech Republic.,Department of Analytical Chemistry, Faculty of Science, Palacky University, Olomouc, Czech Republic
| | - Joachim Pfister
- Department of Nuclear Medicine, Medical University Innsbruck, Anichstrasse 5, A-6020, Innsbruck, Austria
| | - Christian Mair
- Department of Nuclear Medicine, Medical University Innsbruck, Anichstrasse 5, A-6020, Innsbruck, Austria
| | - Zbynek Novy
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, CZ-77900, Olomouc, Czech Republic
| | - Miroslav Popper
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, CZ-77900, Olomouc, Czech Republic
| | - Marian Hajduch
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, CZ-77900, Olomouc, Czech Republic
| | - Clemens Decristoforo
- Department of Nuclear Medicine, Medical University Innsbruck, Anichstrasse 5, A-6020, Innsbruck, Austria.
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7
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Petrik M, Pfister J, Misslinger M, Decristoforo C, Haas H. Siderophore-Based Molecular Imaging of Fungal and Bacterial Infections-Current Status and Future Perspectives. J Fungi (Basel) 2020; 6:E73. [PMID: 32485852 PMCID: PMC7345832 DOI: 10.3390/jof6020073] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/25/2020] [Accepted: 05/27/2020] [Indexed: 12/15/2022] Open
Abstract
Invasive fungal infections such as aspergillosis are life-threatening diseases mainly affecting immuno-compromised patients. The diagnosis of fungal infections is difficult, lacking specificity and sensitivity. This review covers findings on the preclinical use of siderophores for the molecular imaging of infections. Siderophores are low molecular mass chelators produced by bacteria and fungi to scavenge the essential metal iron. Replacing iron in siderophores by radionuclides such as gallium-68 allowed the targeted imaging of infection by positron emission tomography (PET). The proof of principle was the imaging of pulmonary Aspergillus fumigatus infection using [68Ga]Ga-triacetylfusarinine C. Recently, this approach was expanded to imaging of bacterial infections, i.e., with Pseudomonas aeruginosa. Moreover, the conjugation of siderophores and fluorescent dyes enabled the generation of hybrid imaging compounds, allowing the combination of PET and optical imaging. Nevertheless, the high potential of these imaging probes still awaits translation into clinics.
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Affiliation(s)
- Milos Petrik
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 77900 Olomouc, Czech Republic;
| | - Joachim Pfister
- Department of Nuclear Medicine, Medical University Innsbruck, 6020 Innsbruck, Austria;
| | - Matthias Misslinger
- Institute of Molecular Biology, Medical University Innsbruck, 6020 Innsbruck, Austria;
| | - Clemens Decristoforo
- Department of Nuclear Medicine, Medical University Innsbruck, 6020 Innsbruck, Austria;
| | - Hubertus Haas
- Institute of Molecular Biology, Medical University Innsbruck, 6020 Innsbruck, Austria;
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8
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Chuljerm H, Chen YL, Srichairatanakool S, Hider RC, Cilibrizzi A. Synthesis and iron coordination properties of schizokinen and its imide derivative. Dalton Trans 2019; 48:17395-17401. [PMID: 31742278 DOI: 10.1039/c9dt02731a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The iron(iii) affinity constants for schizokinen and its imide derivative are reported for the first time. Surprisingly, schizokinen possesses a higher affinity for iron(iii) than desferrioxamine B; log KFeIII (FeL), 36.2 and 30.6, respectively. This increase in value is associated with the substitution of one hydroxamate function by an α-hydroxycarboxylate grouping. By virtue of the similarity of siderophore-iron(iii) complexes and siderophore-gallium(iii) complexes, schizokinen (which is a Gram positive siderophore) has potential for 68Ga PET-based imaging.
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Affiliation(s)
- Hataichanok Chuljerm
- Institute of Pharmaceutical Science, King's College London, London, SE1 9NH, UK.
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9
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Jain R, Fan S, Kaden P, Tsushima S, Foerstendorf H, Barthen R, Lehmann F, Pollmann K. Recovery of gallium from wafer fabrication industry wastewaters by Desferrioxamine B and E using reversed-phase chromatography approach. WATER RESEARCH 2019; 158:203-212. [PMID: 31035197 DOI: 10.1016/j.watres.2019.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 04/02/2019] [Accepted: 04/05/2019] [Indexed: 06/09/2023]
Abstract
Gallium (Ga) is a critical element in developing renewable energy generation and energy efficient systems. The supply of Ga is at risk and needed recycling technologies for its availability in future. This study demonstrated the recovery of Ga3+ from low gallium concentrated wafer fabrication industry wastewaters using the siderophores desferrioxamine B (DFOB) and desferrioxamine E (DFOE). The complexation of Ga3+ by DFOB and DFOE was through hydroxamate group as demonstrated by infrared spectroscopy, nuclear magnetic resonance and density functional theory calculations. The high selectivity of DFOB/E towards Ga3+ was observed due to the formation of highly stable complex. Indeed, due to the formation of such high stability complex, the DFOB and DFOE were able to successfully complex 100% Ga in the two different process water from wafer fabrication industry. For the recovery of the siderophores, a high rate of decomplexation of Ga (>90%) was achieved upon addition of 6 times excess of ethylenediaminetetraacetic acid (EDTA) at pH of 3.5. More than 95% of Ga-DFOB and Ga-DFOE complex were recovered with purity (% of Ga moles in comparison to total moles of metals) of 69.8 and 92.9%, respectively by application of a C18 reversed-phase chromatography column. This study, for the first time, demonstrated a technical solution to the recovery of Ga3+ from the low concentrated wastewater based on siderophores and reversed-phase chromatography. A German patent application had been filed for this technology.
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Affiliation(s)
- Rohan Jain
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Bautzner Landstrasse 400, 01328, Dresden, Germany.
| | - Siyuan Fan
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Bautzner Landstrasse 400, 01328, Dresden, Germany
| | - Peter Kaden
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstrasse 400, 01328, Dresden, Germany
| | - Satoru Tsushima
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstrasse 400, 01328, Dresden, Germany; Laboratory for Advanced Nuclear Energy, Tokyo Institute of Technology, Meguro, Tokyo, 152-8550, Japan
| | - Harald Foerstendorf
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstrasse 400, 01328, Dresden, Germany
| | - Robert Barthen
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstrasse 400, 01328, Dresden, Germany
| | - Falk Lehmann
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Bautzner Landstrasse 400, 01328, Dresden, Germany
| | - Katrin Pollmann
- Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Bautzner Landstrasse 400, 01328, Dresden, Germany
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10
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A reevaluation of iron binding by Mycobactin J. J Biol Inorg Chem 2018; 23:995-1007. [DOI: 10.1007/s00775-018-1592-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 07/03/2018] [Indexed: 12/21/2022]
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11
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Fazary AE, Al-Shihri AS, Saleh KA, Alfaifi MY, Alshehri MA, Elbehairi SEI. Di- and Tri-valent Metal Ions Interactions with Four Biodegradable Hydroxamate and Cataecholate Siderophores: New Insights into Their Complexation Equilibria. J SOLUTION CHEM 2016. [DOI: 10.1007/s10953-016-0475-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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12
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Meininger DJ, Chee-Garza M, Arman HD, Tonzetich ZJ. Gallium(III) Tetraphenylporphyrinates Containing Hydrosulfide and Thiolate Ligands: Structural Models for Sulfur-Bound Iron(III) Hemes. Inorg Chem 2016; 55:2421-6. [DOI: 10.1021/acs.inorgchem.5b02822] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Daniel J. Meininger
- Department of Chemistry, University of Texas at San Antonio (UTSA), San Antonio Texas 78249, United States
| | - Max Chee-Garza
- Department of Chemistry, University of Texas at San Antonio (UTSA), San Antonio Texas 78249, United States
| | - Hadi D. Arman
- Department of Chemistry, University of Texas at San Antonio (UTSA), San Antonio Texas 78249, United States
| | - Zachary J. Tonzetich
- Department of Chemistry, University of Texas at San Antonio (UTSA), San Antonio Texas 78249, United States
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13
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Fazary AE, Ju YH, Al-Shihri AS, Alfaifi MY, Alshehri MA. Biodegradable siderophores: survey on their production, chelating and complexing properties. REV INORG CHEM 2016. [DOI: 10.1515/revic-2016-0002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractThe academic and industrial research on the interactions of complexing agents with the environment has received more attention for more than half a century ago and has always been concerned with the applications of chelating agents in the environment. In contrast, in recent years, an increasing scholarly interest has been demonstrated in the chemical and biological degradation of chelating agents. This is reflected by the increasing number of chelating agents-related publications between 1950 and middle of 2016. Consequently, the discovery of new green biodegradable chelating agents is of great importance and has an impact in the non-biodegradable chelating agent’s replacement with their green chemistry analogs. To acquire iron, many bacteria growing aerobically, including marine species, produce siderophores, which are low-molecular-weight compounds produced to facilitate acquisition of iron. To date and to the best of our knowledge, this is a concise and complete review article of the current and previous relevant studies conducted in the field of production, purification of siderophore compounds and their metal complexes, and their roles in biology and medicine.
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14
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Dodd EL, Bohle DS. Orienting the heterocyclic periphery: a structural model for chloroquine's antimalarial activity. Chem Commun (Camb) 2014; 50:13765-8. [DOI: 10.1039/c4cc05328a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A fluorescent structurally characterized chloroquine–metalloporphyrin adduct has been prepared and characterized. This allows for new insights into antimalarial drug–heme interactions.
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Affiliation(s)
- Erin L. Dodd
- Department of Chemistry
- McGill University
- Montreal, Canada
| | - D. Scott Bohle
- Department of Chemistry
- McGill University
- Montreal, Canada
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15
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Dimise EJ, Condurso HL, Stoker GE, Bruner SD. Synthesis and structure confirmation of fuscachelins A and B, structurally unique natural product siderophores from Thermobifida fusca. Org Biomol Chem 2012; 10:5353-6. [DOI: 10.1039/c2ob26010g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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16
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Seyedsayamdost MR, Traxler MF, Zheng SL, Kolter R, Clardy J. Structure and biosynthesis of amychelin, an unusual mixed-ligand siderophore from Amycolatopsis sp. AA4. J Am Chem Soc 2011; 133:11434-7. [PMID: 21699219 PMCID: PMC3144690 DOI: 10.1021/ja203577e] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Actinobacteria generate a large number of structurally diverse small molecules with potential therapeutic value. Genomic analyses of this productive group of bacteria show that their genetic potential to manufacture small molecules exceeds their observed ability by roughly an order of magnitude, and this revelation has prompted a number of studies to identify members of the unknown majority. As a potential window into this cryptic secondary metabolome, pairwise assays for developmental interactions within a set of 20 sequenced actinomycetes were carried out. These assays revealed that Amycolatopsis sp. AA4, a so-called “rare” actinomycete, produces a novel siderophore, amychelin, which alters the developmental processes of several neighboring streptomycetes. Using this phenotype as an assay, we isolated amychelin and solved its structure by NMR and MS methods coupled with an X-ray crystallographic analysis of its Fe-complex. The iron binding affinity of amychelin was determined using EDTA competition assays, and a biosynthetic cluster was identified and annotated to provide a tentative biosynthetic scheme for amychelin.
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Affiliation(s)
- Mohammad R Seyedsayamdost
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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17
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Nunes A, Podinovskaia M, Leite A, Gameiro P, Zhou T, Ma Y, Kong X, Schaible UE, Hider RC, Rangel M. Fluorescent 3-hydroxy-4-pyridinone hexadentate iron chelators: intracellular distribution and the relevance to antimycobacterial properties. J Biol Inorg Chem 2010; 15:861-77. [PMID: 20364296 DOI: 10.1007/s00775-010-0650-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Accepted: 03/19/2010] [Indexed: 11/29/2022]
Abstract
We report the synthesis and characterization of a fluorescent iron chelator (4), shown to be effective in inhibiting the growth of Mycobacterium avium in macrophages, together with the synthesis and characterization of two unsuccessful analogues selected to facilitate identification of the molecular properties responsible for the antimicrobial activity. Partition of the chelators in liposomes was investigated and the compounds were assessed with respect to uptake by macrophages, responsiveness to iron overload/iron deprivation and intracellular distribution by flow cytometry and confocal microscopy. The synthesis of the hexadentate chelators is based on a tetrahedral structure to which three bidentate 3-hydroxy-4-pyridinone chelating units are linked via amide bonds. The structure is synthetically versatile, allowing further addition of functional groups such as fluorophores. Here, we analyse the non-functionalized hexadentate unit (3) and the corresponding rhodamine B (4) and fluorescein (5) labelled chelators. The iron(III) stability constant was determined for 3 and the values log beta = 34.4 and pFe(3+) = 29.8 indicate an affinity for iron of the same order of magnitude as that of mycobacteria siderophores. Fluorescence properties in the presence of liposomes show that 4 strongly interacts with the lipid phase, whereas 5 does not. Such different behaviour may explain their distinct intracellular localization as revealed by confocal microscopy. The flow cytometry and confocal microscopy studies indicate that 4 is readily engulfed by macrophages and targeted to cytosol and vesicles of the endolysosomal continuum, whereas 5 is differentially distributed and only partially colocalizes with 4 after prolonged incubation. Differential distribution of the compounds is likely to account for their different efficacy against mycobacteria.
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Affiliation(s)
- Ana Nunes
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, 4069-007, Porto, Portugal
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18
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Affiliation(s)
- Moriah Sandy
- Department of Chemistry & Biochemistry, University of California, Santa Barbara, California 93106-9510, USA
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Manning TJ, Thomas J, Osiro S, Smith J, Abadi G, Noble L, Phillips D. Computational studies of Fe(III) binding to bryostatins, bryostatin analogs, siderophores and marine natural products: arguments for ferric complexes in medicinal applications. Nat Prod Res 2008; 22:399-413. [DOI: 10.1080/14786410701590087] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Wasielewski E, Tzou DL, Dillmann B, Czaplicki J, Abdallah MA, Atkinson RA, Kieffer B. Multiple Conformations of the Metal-Bound Pyoverdine PvdI, a Siderophore of Pseudomonas aeruginosa: A Nuclear Magnetic Resonance Study,. Biochemistry 2008; 47:3397-406. [DOI: 10.1021/bi702214s] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Emeric Wasielewski
- Laboratoire de Biologie et de Génomique Structurales, Biomolecular NMR group, IGBMC UMR 7104 CNRS, ESBS, bd Sébastien Brandt BP 10413, 67404 Illkirch Cedex, France, Institute of Chemistry, Academia Sinica, 128 Yen-Chiu-Yuan Road,Sec. 2, Nankang, Taipei 115, Taiwan, Republic of China, Université Paul Sabatier/Institut de Pharmacologie et de Biologie Structurale CNRS, 205, route de Narbonne, 31077 Toulouse, France, and Département Récepteurs et Protéines Membranaires, UMR 7175 École Supérieure de
| | - Der-Lii Tzou
- Laboratoire de Biologie et de Génomique Structurales, Biomolecular NMR group, IGBMC UMR 7104 CNRS, ESBS, bd Sébastien Brandt BP 10413, 67404 Illkirch Cedex, France, Institute of Chemistry, Academia Sinica, 128 Yen-Chiu-Yuan Road,Sec. 2, Nankang, Taipei 115, Taiwan, Republic of China, Université Paul Sabatier/Institut de Pharmacologie et de Biologie Structurale CNRS, 205, route de Narbonne, 31077 Toulouse, France, and Département Récepteurs et Protéines Membranaires, UMR 7175 École Supérieure de
| | - Baudoin Dillmann
- Laboratoire de Biologie et de Génomique Structurales, Biomolecular NMR group, IGBMC UMR 7104 CNRS, ESBS, bd Sébastien Brandt BP 10413, 67404 Illkirch Cedex, France, Institute of Chemistry, Academia Sinica, 128 Yen-Chiu-Yuan Road,Sec. 2, Nankang, Taipei 115, Taiwan, Republic of China, Université Paul Sabatier/Institut de Pharmacologie et de Biologie Structurale CNRS, 205, route de Narbonne, 31077 Toulouse, France, and Département Récepteurs et Protéines Membranaires, UMR 7175 École Supérieure de
| | - Jerzy Czaplicki
- Laboratoire de Biologie et de Génomique Structurales, Biomolecular NMR group, IGBMC UMR 7104 CNRS, ESBS, bd Sébastien Brandt BP 10413, 67404 Illkirch Cedex, France, Institute of Chemistry, Academia Sinica, 128 Yen-Chiu-Yuan Road,Sec. 2, Nankang, Taipei 115, Taiwan, Republic of China, Université Paul Sabatier/Institut de Pharmacologie et de Biologie Structurale CNRS, 205, route de Narbonne, 31077 Toulouse, France, and Département Récepteurs et Protéines Membranaires, UMR 7175 École Supérieure de
| | - Mohamed A. Abdallah
- Laboratoire de Biologie et de Génomique Structurales, Biomolecular NMR group, IGBMC UMR 7104 CNRS, ESBS, bd Sébastien Brandt BP 10413, 67404 Illkirch Cedex, France, Institute of Chemistry, Academia Sinica, 128 Yen-Chiu-Yuan Road,Sec. 2, Nankang, Taipei 115, Taiwan, Republic of China, Université Paul Sabatier/Institut de Pharmacologie et de Biologie Structurale CNRS, 205, route de Narbonne, 31077 Toulouse, France, and Département Récepteurs et Protéines Membranaires, UMR 7175 École Supérieure de
| | - R. Andrew Atkinson
- Laboratoire de Biologie et de Génomique Structurales, Biomolecular NMR group, IGBMC UMR 7104 CNRS, ESBS, bd Sébastien Brandt BP 10413, 67404 Illkirch Cedex, France, Institute of Chemistry, Academia Sinica, 128 Yen-Chiu-Yuan Road,Sec. 2, Nankang, Taipei 115, Taiwan, Republic of China, Université Paul Sabatier/Institut de Pharmacologie et de Biologie Structurale CNRS, 205, route de Narbonne, 31077 Toulouse, France, and Département Récepteurs et Protéines Membranaires, UMR 7175 École Supérieure de
| | - Bruno Kieffer
- Laboratoire de Biologie et de Génomique Structurales, Biomolecular NMR group, IGBMC UMR 7104 CNRS, ESBS, bd Sébastien Brandt BP 10413, 67404 Illkirch Cedex, France, Institute of Chemistry, Academia Sinica, 128 Yen-Chiu-Yuan Road,Sec. 2, Nankang, Taipei 115, Taiwan, Republic of China, Université Paul Sabatier/Institut de Pharmacologie et de Biologie Structurale CNRS, 205, route de Narbonne, 31077 Toulouse, France, and Département Récepteurs et Protéines Membranaires, UMR 7175 École Supérieure de
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Fokin AA, Yurchenko AG, Rodionov VN, Gunchenko PA, Yurchenko RI, Reichenberg A, Wiesner J, Hintz M, Jomaa H, Schreiner PR. Synthesis of the antimalarial drug FR900098 utilizing the nitroso-ene reaction. Org Lett 2007; 9:4379-82. [PMID: 17887769 DOI: 10.1021/ol702082k] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The antimalarial drug FR900098 was prepared from diethyl allylphosphonate involving the nitroso-ene reaction with nitrosocarbonyl methane as the key step followed by hydrogenation and dealkylation. The utilization of dibenzyl allylphosphonate as the starting compound allows one-step hydrogenation with dealkylation, which simplifies the preparative scheme further.
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Affiliation(s)
- Andrey A Fokin
- Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev, Ukraine.
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Martin JD, Ito Y, Homann VV, Haygood MG, Butler A. Structure and membrane affinity of new amphiphilic siderophores produced by Ochrobactrum sp. SP18. J Biol Inorg Chem 2006; 11:633-41. [PMID: 16791646 DOI: 10.1007/s00775-006-0112-y] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2006] [Accepted: 04/18/2006] [Indexed: 10/24/2022]
Abstract
The coastal alpha-proteobacterium Ochrobactrum sp. SP18 produces a suite of three citrate-derived, cell-associated amphiphilic siderophores, ochrobactins A-C. The ochrobactins are composed of a citric acid backbone amide-linked to two lysine residues. Each epsilon-amine of lysine is hydroxylated and acylated forming two hydroxamic acid moieties. One of the acylated appendages of each ochrobactin is (E)-2-decenoic acid. The other acylated appendages for ochrobactins A-C are (E)-2-octenoic acid, octanoic acid and (E)-2-decenoic acid, respectively. The ferric ochrobactin complexes are photoreactive in UV light, producing an oxidized ligand with loss of 46 mass units that can still coordinate Fe(III). The relative partitioning of the apo-ochrobactins, Fe(III) ochrobactins and Fe(III) photoproducts into 1,2-dimyristoyl-sn-glycero-3-phosphocholine vesicles is presented. The ochrobactins are the first example of aerobactin-based siderophores with two fatty acid appendages produced in a suite with varying acyl appendage lengths.
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Affiliation(s)
- Jessica D Martin
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106-9510, USA
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Abstract
Iron is essential for the growth of nearly all microorganisms yet iron is only sparingly soluble near the neutral pH, aerobic conditions in which many microorganisms grow. The pH of ocean water is even higher, thereby further lowering the concentration of dissolved ferric ion. To compound the problem of availability, the total iron concentration is surprisingly low in surface ocean water, yet nevertheless, marine microorganisms still require iron for growth. Like terrestrial bacterial, bacteria isolated from open ocean water often produce siderophores, which are low molecular weight chelating ligands that facilitate the microbial acquisition of iron. The present review summarizes the structures of siderophores produced by marine bacteria and the emerging characteristics that distinguish marine siderophores.
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Affiliation(s)
- Alison Butler
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93111-9510, USA.
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Luo M, Lin H, Fischbach MA, Liu DR, Walsh CT, Groves JT. Enzymatic tailoring of enterobactin alters membrane partitioning and iron acquisition. ACS Chem Biol 2006; 1:29-32. [PMID: 17163637 DOI: 10.1021/cb0500034] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Enterobactin (Ent), a prototypic bacterial siderophore, is modified by both the C-glucosyltransferase IroB and the macrolactone hydrolase IroE in pathogenic bacteria that contain the iroA cluster. To investigate the possible effects of glucosylation and macrolactone hydrolysis on the physical properties of Ent, the membrane affinities and iron acquisition rates of Ent and Ent-derived siderophores were measured. The data obtained indicate that Ent has a high membrane affinity (K(x) = 1.5 x 10(4)) similar to that of ferric acinetoferrin, an amphiphile containing two eight-carbon hydrophobic chains. Glucosylation and macrolactone hydrolysis decrease the membrane affinity of Ent by 5-25-fold. Furthermore, in the presence of phospholipid vesicles, the iron acquisition rate is significantly increased by glucosylation and macrolactone hydrolysis, due to the resultant decrease in membrane sequestration of the siderophore. These results suggest that IroB and IroE enhance the ability of Ent-producing pathogens to acquire iron in membrane-rich microenvironments.
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Fadeev EA, Luo M, Groves JT. Synthesis and structural modeling of the amphiphilic siderophore rhizobactin-1021 and its analogs. Bioorg Med Chem Lett 2005; 15:3771-4. [PMID: 15990296 DOI: 10.1016/j.bmcl.2005.05.114] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2005] [Revised: 05/13/2005] [Accepted: 05/16/2005] [Indexed: 11/22/2022]
Abstract
We describe two convenient syntheses of rhizobactin-1021 (Rz), a citrate-based siderophore amphiphile produced by the nitrogen-fixing root symbiont Rhizobium meliloti-1021, and several analogs. Our approach features a singly amidated, tert-butyl-protected citrate intermediate that easily affords a variety of Rz analogs in the late stages of the synthesis. Structural modeling and the monolayer behavior of Rz and its metal complexes are consistent with a structural reorganization upon Rz-mediated iron chelation.
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Affiliation(s)
- Evgeny A Fadeev
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
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Luo M, Fadeev EA, Groves JT. Mycobactin-mediated iron acquisition within macrophages. Nat Chem Biol 2005; 1:149-53. [PMID: 16408019 DOI: 10.1038/nchembio717] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2005] [Accepted: 06/13/2005] [Indexed: 11/08/2022]
Abstract
Restricting the availability of iron is an important strategy for defense against bacterial infection. Mycobacterium tuberculosis survives within the phagosomes of macrophages; consequently, iron acquisition is particularly difficult for M. tuberculosis, because the phagosomal membrane is an additional barrier for its iron access. However, little is known about the iron transport and acquisition pathways adapted by this microbe in vivo. Extracellular iron sources are usually mobilized by hydrophilic siderophores. Here, we describe direct evidence that mycobactins, the lipophilic siderophores of mycobacteria, efficiently extract intracellular macrophage iron. The metal-free siderophore is diffusely associated with the macrophage membrane, ready for iron chelation. Notably, the mycobactin-metal complex accumulates with high selectivity in macrophage lipid droplets, intracellular domains for lipid storage and sorting. In our experiments, these mycobactin-targeted lipid droplets were found in direct contact with phagosomes, poised for iron delivery. The existence of this previously undescribed iron acquisition pathway indicates that mycobacteria have taken advantage of endogenous macrophage mechanisms for iron mobilization and lipid sorting for iron acquisition during infection. The pathway could represent a new target for the control of mycobacterial infection.
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Affiliation(s)
- Minkui Luo
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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Luo M, Fadeev EA, Groves JT. Membrane Dynamics of the Amphiphilic Siderophore, Acinetoferrin. J Am Chem Soc 2005; 127:1726-36. [PMID: 15701007 DOI: 10.1021/ja044230f] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Acinetobacter haemolyticus is an antibiotic resistant, pathogenic bacterium responsible for an increasing number of hospital infections. Acinetoferrin (Af), the amphiphilic siderophore isolated from this organism, contains two unusual trans-2-octenoyl hydrocarbon chains reminiscent of a phospholipid structural motif. Here, we have investigated the membrane affinity of Af and its iron complex, Fe-Af, using small and large unilamellar phospholipid vesicles (SUV and LUV) as model membranes. Af shows a high membrane affinity with a partition coefficient, K(x)= 6.8 x 10(5). Membrane partitioning and trans-membrane flip-flop of Fe-Af have also been studied via fluorescence quenching of specifically labeled vesicle leaflets and (1)H NMR line-broadening techniques. Fe-Af is found to rapidly redistribute between lipid and aqueous phases with dissociation/partitioning rates of k(off) = 29 s(-1) and k(on) = 2.4 x 10(4) M(-1) s(-1), respectively. Upon binding iron, the membrane affinity of Af is reduced 30-fold to K'(x) = 2.2 x 10(4) for Fe-Af. In addition, trans-membrane flip-flop of Fe-Af occurs with a rate constant, k(p) = 1.2 x 10(-3) s(-1), with egg-PC LUV and a half-life time around 10 min with DMPC SUV. These properties are due to the phospholipid-like conformation of Af and the more extended conformation of Fe-Af that is enforced by iron binding. Remarkable similarities and differences between Af and another amphiphilic siderophore, marinobactin E, are discussed. The potential biological implications of Af and Fe-Af are also addressed. Our approaches using inner- and outer-leaflet-labeled fluorescent vesicles and (1)H NMR line-broadening techniques to discern Af-mediated membrane partitioning and trans-membrane diffusion are amenable to similar studies for other paramagnetic amphiphiles.
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Affiliation(s)
- Minkui Luo
- Department of Chemistry, Princeton University, Princeton, NJ 08540, USA
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Tzou DL, Wasielewski E, Abdallah MA, Kieffer B, Atkinson RA. A low-temperature heteronuclear NMR study of two exchanging conformations of metal-bound pyoverdin PaA fromPseudomonas aeruginosa. Biopolymers 2005; 79:139-49. [PMID: 16078193 DOI: 10.1002/bip.20343] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Under iron-deficient conditions, the Gram-negative bacterium Pseudomonas aeruginosa ATCC 15692 secretes a peptidic siderophore, pyoverdin PaA, composed of an aromatic chromophore derived from 2,3-diamino-6,7-dihydroxyquinoline and a partially cyclized octapeptide, D-Ser-L-Arg-D-Ser-L-FoOHOrn-(L-Lys-L-FoOHOrn-L-Thr-L-Thr) (FoOHOrn: delta N-formyl-delta N-hydroxyornithine), in which the C-terminal carboxyl group forms a peptidic bond with the primary amine of the L-Lys side chain. Ferric iron is chelated by the catechol group on the chromophore and the two hydroxyornithine side chains. In aqueous solution, the (1)H-NMR spectrum of pyoverdin PaA-Ga(III), in which Ga(III) is used instead of Fe(III) for spectroscopic purposes, showed clear evidence of exchange broadening, preventing further structural characterization. The use of cryo-solvents allowed measurements to be made at temperatures as low as 253 K where two distinct conformations with roughly equivalent populations could be observed. (13)C and (15)N labeling of pyoverdin PaA enabled complete assignment of both forms of pyoverdin PaA-Ga(III) at 253 and 267 K, using triple-resonance multidimensional NMR experiments commonly applied to doubly labeled proteins.
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Affiliation(s)
- Der-Lii Tzou
- Institute of Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan, Republic of China
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