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Abstract
This review deals with the synthesis of naturally occurring alkaloids containing partially or completely saturated pyrimidine nuclei. The interest in these compounds is associated with their structural diversity, high biological activity and toxicity. The review is divided into four parts, each of which describes a number of synthetic methodologies toward structurally different naturally occurring alkaloids containing saturated cyclic six-membered amidine, guanidine, aminal and urea (thiourea) moieties, respectively. The development of various synthetic strategies for the preparation of these compounds has remarkably increased during the past few decades. This is primarily due to the fact that some of these compounds are isolated only in limited quantities, which makes it practically impossible to study their full structural characteristics and biological activity.
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Bouvier B, Cézard C. Impact of iron coordination isomerism on pyoverdine recognition by the FpvA membrane transporter of Pseudomonas aeruginosa. Phys Chem Chem Phys 2017; 19:29498-29507. [PMID: 29082401 DOI: 10.1039/c7cp04529h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Pyoverdines, the primary siderophores of Pseudomonas bacteria, scavenge the iron essential to bacterial life in the outside medium and transport it back into the periplasm. Despite their relative simplicity, pyoverdines feature remarkably flexible recognition characteristics whose origins at the atomistic level remain only partially understood: the ability to bind other metals than ferric iron, the capacity of outer membrane transporters to recognize and internalize noncognate pyoverdines from other pseudomonads… One of the less examined factors behind this polymorphic recognition lies in the ability for pyoverdines to bind iron with two distinct chiralities, at the cost of a conformational switch. Herein, we use free energy simulations to study how the stereochemistry of the iron chelating groups influences the structure and dynamics of two common pyoverdines and impacts their recognition by the FpvA membrane transporter of P. aeruginosa. We show that conformational preferences for one metal binding chirality over the other, observed in solution depending on the nature of the pyoverdine, are canceled out by the FpvA transporter, which recognizes both chiralities equally well for both pyoverdines under study. However, FpvA discriminates between pyoverdines by altering the kinetics of stereoisomer interconversion. We present structural causes of this intriguing recognition mechanism and discuss its possible significance in the context of the competitive scavenging of iron.
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Affiliation(s)
- Benjamin Bouvier
- Laboratoire de Glycochimie, des Antimicrobiens et des Agroressources, CNRS UMR7378/Université de Picardie Jules Verne, 10 rue Baudelocque, 80039 Amiens Cedex, France.
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3
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Ringel MT, Dräger G, Brüser T. The periplasmic transaminase PtaA of Pseudomonas fluorescens converts the glutamic acid residue at the pyoverdine fluorophore to α-ketoglutaric acid. J Biol Chem 2017; 292:18660-18671. [PMID: 28912270 DOI: 10.1074/jbc.m117.812545] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 09/13/2017] [Indexed: 11/06/2022] Open
Abstract
The periplasmic conversion of ferribactin to pyoverdine is essential for siderophore biogenesis in fluorescent pseudomonads, such as pathogenic Pseudomonas aeruginosa or plant growth-promoting Pseudomonas fluorescens The non-ribosomal peptide ferribactin undergoes cyclizations and oxidations that result in the fluorophore, and a strictly conserved fluorophore-bound glutamic acid residue is converted to a range of variants, including succinamide, succinic acid, and α-ketoglutaric acid residues. We recently discovered that the pyridoxal phosphate-containing enzyme PvdN is responsible for the generation of the succinamide, which can be hydrolyzed to succinic acid. Based on this, a distinct unknown enzyme was postulated to be responsible for the conversion of the glutamic acid to α-ketoglutaric acid. Here we report the identification and characterization of this enzyme in P. fluorescens strain A506. In silico analyses indicated a periplasmic transaminase in fluorescent pseudomonads and other proteobacteria that we termed PtaA for "periplasmic transaminase A" An in-frame-deleted ptaA mutant selectively lacked the α-ketoglutaric acid form of pyoverdine, and recombinant PtaA complemented this phenotype. The ptaA/pvdN double mutant produced exclusively the glutamic acid form of pyoverdine. PtaA is homodimeric and contains a pyridoxal phosphate cofactor. Mutation of the active-site lysine abolished PtaA activity and affected folding as well as Tat-dependent transport of the enzyme. In pseudomonads, the occurrence of ptaA correlates with the occurrence of α-ketoglutaric acid forms of pyoverdines. As this enzyme is not restricted to pyoverdine-producing bacteria, its catalysis of periplasmic transaminations is most likely a general tool for specific biosynthetic pathways.
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Affiliation(s)
- Michael T Ringel
- From the Institute of Microbiology, Leibniz Universität Hannover, Herrenhäuser Strasse 2, 30419 Hannover, Germany and
| | - Gerald Dräger
- the Institute of Organic Chemistry, Leibniz Universität Hannover, Schneiderberg 1 B, 30167 Hannover, Germany
| | - Thomas Brüser
- From the Institute of Microbiology, Leibniz Universität Hannover, Herrenhäuser Strasse 2, 30419 Hannover, Germany and
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4
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Schalk IJ, Mislin GLA. Bacterial Iron Uptake Pathways: Gates for the Import of Bactericide Compounds. J Med Chem 2017; 60:4573-4576. [DOI: 10.1021/acs.jmedchem.7b00554] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Isabelle J. Schalk
- Université de Strasbourg, UMR7242, ESBS, Boulevard Sébastien Brant, F-67413 Illkirch, France
- CNRS, UMR7242, ESBS, Boulevard
Sébastien Brant, F-67413 Illkirch, France
| | - Gaëtan L. A. Mislin
- Université de Strasbourg, UMR7242, ESBS, Boulevard Sébastien Brant, F-67413 Illkirch, France
- CNRS, UMR7242, ESBS, Boulevard
Sébastien Brant, F-67413 Illkirch, France
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5
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Bouvier B, Cézard C, Sonnet P. Selectivity of pyoverdine recognition by the FpvA receptor of Pseudomonas aeruginosa from molecular dynamics simulations. Phys Chem Chem Phys 2015; 17:18022-34. [PMID: 26098682 DOI: 10.1039/c5cp02939b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Gram-negative bacterium Pseudomonas aeruginosa, a ubiquitous human opportunistic pathogen, has developed resistances to multiple antibiotics. It uses its primary native siderophore, pyoverdine, to scavenge the iron essential to its growth in the outside medium and transport it back into its cytoplasm. The FpvA receptor on the bacterial outer membrane recognizes and internalizes pyoverdine bearing its iron payload, but can also bind pyoverdines from other Pseudomonads or synthetic analogues. Pyoverdine derivatives could therefore be used as vectors to deliver antibiotics into the bacterium. In this study, we use molecular dynamics and free energy calculations to characterize the mechanisms and thermodynamics of the recognition of the native pyoverdines of P. aeruginosa and P. fluorescens by FpvA. Based on these results, we delineate the features that pyoverdines with high affinity for FpvA should possess. In particular, we show that (i) the dynamics and interaction of the unbound pyoverdines with water should be optimized with equal care as the interface contacts in the complex with FpvA; (ii) the C-terminal extremity of the pyoverdine chain, which appears to play no role in the bound complex, is involved in the intermediate stages of recognition; and (iii) the length and cyclicity of the pyoverdine chain can be used to fine-tune the kinetics of the recognition mechanism.
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Affiliation(s)
- Benjamin Bouvier
- Laboratoire de Glycochimie, des Antimicrobiens et des Agroressources, CNRS FRE3517/Université de Picardie Jules Verne, 1, rue des Louvels, 80037 Amiens Cedex 1, France.
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6
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Llamas MA, Imperi F, Visca P, Lamont IL. Cell-surface signaling inPseudomonas: stress responses, iron transport, and pathogenicity. FEMS Microbiol Rev 2014; 38:569-97. [DOI: 10.1111/1574-6976.12078] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 05/20/2014] [Accepted: 05/27/2014] [Indexed: 01/06/2023] Open
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7
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Parker DL, Lee SW, Geszvain K, Davis RE, Gruffaz C, Meyer JM, Torpey JW, Tebo BM. Pyoverdine synthesis by the Mn(II)-oxidizing bacterium Pseudomonas putida GB-1. Front Microbiol 2014; 5:202. [PMID: 24847318 PMCID: PMC4019867 DOI: 10.3389/fmicb.2014.00202] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 04/16/2014] [Indexed: 11/13/2022] Open
Abstract
When iron-starved, the Mn(II)-oxidizing bacteria Pseudomonas putida strains GB-1 and MnB1 produce pyoverdines (PVDGB-1 and PVDMnB1), siderophores that both influence iron uptake and inhibit manganese(II) oxidation by these strains. To explore the properties and genetics of a PVD that can affect manganese oxidation, LC-MS/MS, and various siderotyping techniques were used to identify the peptides of PVDGB-1 and PVDMnB1 as being (for both PVDs): chromophore-Asp-Lys-OHAsp-Ser-Gly-aThr-Lys-cOHOrn, resembling a structure previously reported for P. putida CFML 90-51, which does not oxidize Mn. All three strains also produced an azotobactin and a sulfonated PVD, each with the peptide sequence above, but with unknown regulatory or metabolic effects. Bioinformatic analysis of the sequenced genome of P. putida GB-1 suggested that a particular non-ribosomal peptide synthetase (NRPS), coded by the operon PputGB1_4083-4086, could produce the peptide backbone of PVDGB-1. To verify this prediction, plasmid integration disruption of PputGB1_4083 was performed and the resulting mutant failed to produce detectable PVD. In silico analysis of the modules in PputGB1_4083-4086 predicted a peptide sequence of Asp-Lys-Asp-Ser-Ala-Thr-Lsy-Orn, which closely matches the peptide determined by MS/MS. To extend these studies to other organisms, various Mn(II)-oxidizing and non-oxidizing isolates of P. putida, P. fluorescens, P. marincola, P. fluorescens-syringae group, P. mendocina-resinovorans group, and P. stutzerii group were screened for PVD synthesis. The PVD producers (12 out of 16 tested strains) were siderotyped and placed into four sets of differing PVD structures, some corresponding to previously characterized PVDs and some to novel PVDs. These results combined with previous studies suggested that the presence of OHAsp or the flexibility of the pyoverdine polypeptide may enable efficient binding of Mn(III).
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Affiliation(s)
- Dorothy L. Parker
- Geosciences Research Division, Scripps Institution of Oceanography, University of California San DiegoLa Jolla, CA, USA
| | - Sung-Woo Lee
- Division of Environmental and Biomolecular Systems, Oregon Health and Science UniversityBeaverton, OR, USA
| | - Kati Geszvain
- Division of Environmental and Biomolecular Systems, Oregon Health and Science UniversityBeaverton, OR, USA
| | - Richard E. Davis
- Division of Environmental and Biomolecular Systems, Oregon Health and Science UniversityBeaverton, OR, USA
| | - Christelle Gruffaz
- Laboratoire de Génétique Moléculaire, Génomique et Microbiologie, Université de StrasbourgStrasbourg, France
| | - Jean-Marie Meyer
- Laboratoire de Génétique Moléculaire, Génomique et Microbiologie, Université de StrasbourgStrasbourg, France
| | - Justin W. Torpey
- Biomolecular Mass Spectrometry Facility, Department of Chemistry and Biochemistry, University of California San DiegoLa Jolla, CA, USA
| | - Bradley M. Tebo
- Division of Environmental and Biomolecular Systems, Oregon Health and Science UniversityBeaverton, OR, USA
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Mislin GLA, Schalk IJ. Siderophore-dependent iron uptake systems as gates for antibiotic Trojan horse strategies against Pseudomonas aeruginosa. Metallomics 2014; 6:408-20. [PMID: 24481292 DOI: 10.1039/c3mt00359k] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen responsible for nosocomial infections. The prevalence of antibiotic-resistant P. aeruginosa strains is increasing, necessitating the urgent development of new strategies to improve the control of this pathogen. Its bacterial envelope constitutes of an outer and an inner membrane enclosing the periplasm. This structure plays a key role in the resistance of the pathogen, by decreasing the penetration and the biological impact of many antibiotics. However, this barrier may also be seen as the "Achilles heel" of the bacterium as some of its functions provide opportunities for breaching bacterial defenses. Siderophore-dependent iron uptake systems act as gates in the bacterial envelope and could be used in a "Trojan horse" strategy, in which the conjugation of an antibiotic to a siderophore could significantly increase the biological activity of the antibiotic, by enhancing its transport into the bacterium. In this review, we provide an overview of the various siderophore-antibiotic conjugates that have been developed for use against P. aeruginosa and show that an accurate knowledge of the structural and functional features of the proteins involved in this transmembrane transport is required for the design and synthesis of effective siderophore-antibiotic Trojan horse conjugates.
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Affiliation(s)
- Gaëtan L A Mislin
- UMR 7242, Université de Strasbourg-CNRS, ESBS, 300 Boulevard, Sébastien Brant, F-67413 Illkirch, Strasbourg, France.
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9
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Affiliation(s)
- Roi Mashiach
- Department of Chemistry and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Be’er-Sheva 84105, Israel
| | - Michael M. Meijler
- Department of Chemistry and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Be’er-Sheva 84105, Israel
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Hannauer M, Braud A, Hoegy F, Ronot P, Boos A, Schalk IJ. The PvdRT-OpmQ efflux pump controls the metal selectivity of the iron uptake pathway mediated by the siderophore pyoverdine in Pseudomonas aeruginosa. Environ Microbiol 2011; 14:1696-708. [PMID: 22187978 DOI: 10.1111/j.1462-2920.2011.02674.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pyoverdine (PVD) is the major siderophore produced by Pseudomonas aeruginosa for iron acquisition. PvdRT-OpmQ is an ATP-dependent efflux pump involved in the secretion of newly synthesized pyoverdine (PVD) and of PVD that has transported and released its iron into the bacterium from the periplasm into the extracellular medium. This iron uptake pathway also involves an outer membrane transporter, FpvA, for PVD-Fe uptake from the extracellular medium into the periplasm. In binding assays, FpvA bound PVD in complex with many different metals, with affinities from 2.9 nM for PVD-Fe to 13 µM for PVD-Al. Uptake assays with various FpvA and PvdRT-OpmQ mutants, monitored by inductively coupled plasma-atomic emission spectrometry (ICP-AES) for metal detection, and by fluorescence for PVD detection, showed that both metals and PVD accumulated in P. aeruginosa, due to the uptake of these compounds via the FpvA/PVD pathway. Higher levels of accumulation were observed in the absence of PvdRT-OpmQ expression. Thus, FpvA has a broad metal specificity for both the binding and uptake of PVD-metal complexes, and the PvdRT-OpmQ efflux pump exports unwanted metals complexed with PVD from the bacterium. This study provides the first evidence of efflux pump involvement in the export of unwanted siderophore-metal complexes and insight into the molecular mechanisms involved controlling the metal selectivity of siderophore-mediated iron uptake pathways.
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Affiliation(s)
- Mélissa Hannauer
- Université de Strasbourg-CNRS, Blvd Sébastien Brant, Illkirch, Strasbourg, France
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11
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Doorneweerd DD, Henne WA, Reifenberger RG, Low PS. Selective capture and identification of pathogenic bacteria using an immobilized siderophore. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:15424-15429. [PMID: 20704340 DOI: 10.1021/la101962w] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Rapid identification of infectious pathogens constitutes an important step toward limiting the spread of contagious diseases. Whereas antibody-based detection strategies are often selected because of their speed, mutation of the pathogen can render such tests obsolete. In an effort to develop a rapid yet mutation-proof method for pathogen identification, we have explored the use of "immutable ligands" to capture the desired microbe on a detection device. In this "proof-of-principle" study, we immobilize pyoverdine, a siderophore that Pseudomonas aeruginosa must bind to obtain iron, onto gold-plated glass chips and then examine the siderophore's ability to capture P. aeruginosa for its subsequent identification. We demonstrate that exposure of pyoverdine-coated chips to increasing dilutions of P. aeruginosa allows detection of the bacterium down to concentrations as low as 10(2)/mL. We further demonstrate that printing of the siderophore in a periodic pattern on the detection chip enables a sensitive method of detecting the bound pathogen by a Fourier transform analysis of light scattered by the patterned chip. Because unrelated bacteria are not captured on the pyoverdine chip, we conclude that pyoverdine can be exploited for the specific binding and identification of P. aeruginosa. It follows that the utilization of other microbe-specific "immutable ligands" may allow the specific identification of their cognate pathogens.
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Affiliation(s)
- Derek D Doorneweerd
- Department of Chemistry, 560 Oval Drive, Purdue University, West Lafayette, Indiana 47907, USA
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Greenwald J, Nader M, Celia H, Gruffaz C, Geoffroy V, Meyer JM, Schalk IJ, Pattus F. FpvA bound to non-cognate pyoverdines: molecular basis of siderophore recognition by an iron transporter. Mol Microbiol 2009; 72:1246-59. [PMID: 19504741 DOI: 10.1111/j.1365-2958.2009.06721.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The first step in the specific uptake of iron via siderophores in Gram-negative bacteria is the recognition and binding of a ferric siderophore by its cognate receptor. We investigated the molecular basis of this event through structural and biochemical approaches. FpvA, the pyoverdine-Fe transporter from Pseudomonas aeruginosa ATCC 15692 (PAO1 strain), is able to transport ferric-pyoverdines originating from other species, whereas most fluorescent pseudomonads are only able to use the one they produce among the more than 100 known different pyoverdines. We solved the structure of FpvA bound to non-cognate pyoverdines of high- or low-affinity and found a close correlation between receptor-ligand structure and the measured affinities. The structure of the first amino acid residues of the pyoverdine chain distinguished the high- and low-affinity binders while the C-terminal portion of the pyoverdines, often cyclic, does not appear to contribute extensively to the interaction between the siderophore and its transporter. The specificity of the ferric-pyoverdine binding site of FpvA is conferred by the structural elements common to all ferric-pyoverdines, i.e. the chromophore, iron, and its chelating groups.
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Affiliation(s)
- Jason Greenwald
- Laboratoire de Biologie Structurale des Membranes, UMR7175, Ecole Supérieure de Biotechnologie de Strasbourg, Bd Sébastien Brant, BP10413, 67412 Illkirch, France.
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13
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Structure-function relationships in the bifunctional ferrisiderophore FpvA receptor from Pseudomonas aeruginosa. Biometals 2009; 22:671-8. [PMID: 19153809 DOI: 10.1007/s10534-008-9203-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Accepted: 12/29/2008] [Indexed: 10/21/2022]
Abstract
FpvA is the primary outer membrane transporter required for iron acquisition via the siderophore pyoverdine (Pvd) in Pseudomonas aeruginosa. FpvA, like other ferrisiderophore transporters, consists of a membrane-spanning beta-barrel occluded by a plug domain. The beta-strands of the barrel are connected by large extracellular loops and periplasmic turns. Like some other TonB-dependent transporters, FpvA has a periplasmic domain involved in a signalling cascade that regulates expression of genes required for ferrisiderophore transport. Here, the structures of FpvA in different loading states are analysed in light of mutagenesis data. This analysis highlights the roles of different protein domains in Pvd-Fe uptake and the signalling cascade and reveals a strong correlation between Pvd-Fe transport and activation of the signalling cascade. It is likely that conclusions drawn for FpvA will be relevant to other TonB-dependent ferrisiderophore transport and signalling proteins.
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Braud A, Hoegy F, Jezequel K, Lebeau T, Schalk IJ. New insights into the metal specificity of the Pseudomonas aeruginosa pyoverdine-iron uptake pathway. Environ Microbiol 2009; 11:1079-91. [PMID: 19207567 DOI: 10.1111/j.1462-2920.2008.01838.x] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pyoverdine (PvdI) is the major siderophore secreted by Pseudomonas aeruginosa PAOI in order to get access to iron. After being loaded with iron in the extracellular medium, PvdI is transported across the bacterial outer membrane by the transporter, FpvAI. We used the spectral properties of PvdI to show that in addition to Fe(3+), this siderophore also chelates, but with lower efficiencies, all the 16 metals used in our screening. Afterwards, FpvAI at the cell surface binds Ag(+), Al(3+), Cd(2+), Co(2+), Cu(2+), Fe(3+), Ga(3+), Hg(2+), Mn(2+), Ni(2+) or Zn(2+) in complex with PvdI. We used Inductively Coupled Plasma-Atomic Emission Spectrometry to monitor metal uptake in P. aeruginosa: TonB-dependent uptake, in the presence of PvdI, was only efficient for Fe(3+). Cu(2+), Ga(3+), Mn(2+) and Ni(2+) were also transported into the cell but with lower uptake rates. The presence of Al(3+), Cu(2+), Ga(3+), Mn(2+), Ni(2+) and Zn(2+) in the extracellular medium induced PvdI production in P. aeruginosa. All these data allow a better understanding of the behaviour of the PvdI uptake pathway in the presence of metals other than iron: FpvAI at the cell surface has broad metal specificity at the binding stage and it is highly selective for Fe(3+) only during the uptake process.
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Affiliation(s)
- Armelle Braud
- Métaux et Microorganismes, Chimie, Biologie et Applications, UMR 7175-LC1, CNRS-Université Louis Pasteur, ESBS, Illkirch, Strasbourg, France
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16
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The metal dependence of pyoverdine interactions with its outer membrane receptor FpvA. J Bacteriol 2008; 190:6548-58. [PMID: 18641139 DOI: 10.1128/jb.00784-08] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To acquire iron, Pseudomonas aeruginosa secretes the fluorescent siderophore pyoverdine (Pvd), which chelates iron and shuttles it into the cells via the specific outer membrane transporter FpvA. We studied the role of iron and other metals in the binding and transport of Pvd by FpvA and conclude that there is no significant affinity between FpvA and metal-free Pvd. We found that the fluorescent in vivo complex of iron-free FpvA-Pvd is in fact a complex with aluminum (FpvA-Pvd-Al) formed from trace aluminum in the growth medium. When Pseudomonas aeruginosa was cultured in a medium that had been treated with a metal affinity resin, the in vivo formation of the FpvA-Pvd complex and the recycling of Pvd on FpvA were nearly abolished. The accumulation of Pvd in the periplasm of Pseudomonas aeruginosa was also reduced in the treated growth medium, while the addition of 1 microM AlCl(3) to the treated medium restored the effects of trace metals observed in standard growth medium. Using fluorescent resonance energy transfer and surface plasmon resonance techniques, the in vitro interactions between Pvd and detergent-solubilized FpvA were also shown to be metal dependent. We demonstrated that FpvA binds Pvd-Fe but not Pvd and that Pvd did not compete with Pvd-Fe for FpvA binding. In light of our finding that the Pvd-Al complex is transported across the outer membrane of Pseudomonas aeruginosa, a model for siderophore recognition based on a metal-induced conformation followed by redox selectivity for iron is discussed.
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Schalk IJ. Metal trafficking via siderophores in Gram-negative bacteria: Specificities and characteristics of the pyoverdine pathway. J Inorg Biochem 2008; 102:1159-69. [DOI: 10.1016/j.jinorgbio.2007.11.017] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 10/03/2007] [Accepted: 11/30/2007] [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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Voulhoux R, Filloux A, Schalk IJ. Pyoverdine-mediated iron uptake in Pseudomonas aeruginosa: the Tat system is required for PvdN but not for FpvA transport. J Bacteriol 2006; 188:3317-23. [PMID: 16621825 PMCID: PMC1447448 DOI: 10.1128/jb.188.9.3317-3323.2006] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Under iron-limiting conditions, Pseudomonas aeruginosa PAO1 secretes a fluorescent siderophore called pyoverdine (Pvd). After chelating iron, this ferric siderophore is transported back into the cells via the outer membrane receptor FpvA. The Pvd-dependent iron uptake pathway requires several essential genes involved in both the synthesis of Pvd and the uptake of ferric Pvd inside the cell. A previous study describing the global phenotype of a tat-deficient P. aeruginosa strain showed that the defect in Pvd-mediated iron uptake was due to the Tat-dependent export of proteins involved in Pvd biogenesis and ferric Pvd uptake (U. Ochsner, A. Snyder, A. I. Vasil, and M. L. Vasil, Proc. Natl. Acad. Sci. USA 99:8312-8317, 2002). Using biochemical and biophysical tools, we showed that despite its predicted Tat signal sequence, FpvA is correctly located in the outer membrane of a tat mutant and is fully functional for all steps of the iron uptake process (ferric Pvd uptake and recycling of Pvd on FpvA after iron release). However, in the tat mutant, no Pvd was produced. This suggested that a key element in the Pvd biogenesis pathway must be exported to the periplasm by the Tat pathway. We located PvdN, a still unknown but essential component in Pvd biogenesis, at the periplasmic side of the cytoplasmic membrane and showed that its export is Tat dependent. Our results further support the idea that a critical step of the Pvd biogenesis pathway involving PvdN occurs at the periplasmic side of the cytoplasmic membrane.
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