The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Kenneth N. Raymond - One of the best experts on this subject based on the ideXlab platform.
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parsing the functional specificity of Siderocalin lipocalin 2 ngal for siderophores and related small molecule ligands
Journal of Structural Biology, 2019Co-Authors: Matthew C. Clifton, Kenneth N. Raymond, Peter B Rupert, Trisha M Hoette, Rebecca J Abergel, Roland K. StrongAbstract:Siderocalin/Lipocalin 2/Neutrophil Gelatinase Associated Lipocalin/24p3 is an innate immune system protein with bacteriostatic activity, acting by tightly binding and sequestering diverse catecholate and mixed-type ferric siderophores from enteric bacteria and mycobacteria. Bacterial virulence achieved through siderophore modifications, or utilization of alternate siderophores, can be explained by evasion of Siderocalin binding. Siderocalin has also been implicated in a wide variety of disease processes, though often in seemingly contradictory ways, and has been proposed to bind to a broader array of ligands beyond siderophores. Using structural, directed mutational, and binding studies, we have sought to rigorously test, and fully elucidate, the Siderocalin recognition mechanism. Several proposed ligands fail to meet rigorous binding criteria, including the bacterial siderophore pyochelin, the iron-chelating catecholamine hormone norepinephrine, and the bacterial second messenger cyclic diguanylate monophosphate. While possessing a remarkably rigid structure, in principle simplifying analyses of ligand recognition, understanding Scn recognition is complicated by the observed conformational and stoichiometric plasticity, and instability, of its bona fide siderophore ligands. Since the role of Siderocalin at the early host/pathogen interface is to compete for bacterial ferric siderophores, we also analyzed how bacterial siderophore binding proteins and enzymes alternately recognize siderophores that efficiently bind to, or evade, Siderocalin sequestration - including determining the crystal structure of Bacillus cereus YfiY bound to schizokinen. These studies combine to refine the potential physiological functions of Siderocalin by defining its multiplexed recognition mechanism.
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Siderocalin outwits the coordination chemistry of vibriobactin a siderophore of vibrio cholerae
ACS Chemical Biology, 2013Co-Authors: Benjamin E Allred, Matthew C. Clifton, Roland K. Strong, Colin Correnti, Kenneth N. RaymondAbstract:The human protein Siderocalin (Scn) inhibits bacterial iron acquisition by binding catechol siderophores. Several pathogenic bacteria respond by making stealth siderophores that are not recognized by Scn. Fluvibactin and vibriobactin, respectively of Vibrio fluvialis and Vibrio cholerae, include an oxazoline adjacent to a catechol. This chelating unit binds iron either in a catecholate or a phenolate-oxazoline coordination mode. The latter has been suggested to make vibriobactin a stealth siderophore without directly identifying the coordination mode in relation to Scn binding. We use Scn binding assays with the two siderophores and two oxazoline-substituted analogs and the crystal structure of Fe-fluvibactin:Scn to show that the oxazoline does not prevent Scn binding; hence, vibriobactin is not a stealth siderophore. We show that the phenolate-oxazoline coordination mode is present at physiological pH and is not bound by Scn. However, Scn binding shifts the coordination to the catecholate mode and thereb...
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Siderocalin combats mycobacterial infections
2013Co-Authors: Benjamin E Allred, Allyson K Sia, Kenneth N. RaymondAbstract:The human immunoprotein Siderocalin (Scn) protects against infections by binding the siderophores used by a pathogen to steal iron from host iron stores, thereby limiting bacterial growth and subsequent colonization by restricting the supply of iron. Mycobacterium tuberculosis synthesizes two siderophores, mycobactin and carboxymycobactin, with the same core structure. Unlike the alkyl side chain of mycobactin, the carboxylate chain of carboxymycobactin imparts water solubility on this siderophore, allowing it to be excreted. The variable length of the carboxymycobactin chain markedly influences binding by Scn. The structural differences in the side chains of mycobactin and carboxymycobactin and the intracellular location of M. tuberculosis challenge the ability of Scn to recognize and inactivate siderophore-mediated iron acquisition by this pathogen. We describe the physical interactions between Scn and carboxymycobactin as well as the effect of Scn on the growth of M. tuberculosis in different cellular environments. The evidence suggests that Scn is part of the defenses that prevent or limit infections of M. tuberculosis.
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Siderocalin Outwits the Coordination Chemistry of Vibriobactin, a Siderophore of Vibrio cholerae
2013Co-Authors: Benjamin E. Allred, Matthew C. Clifton, Roland K. Strong, Colin Correnti, Kenneth N. RaymondAbstract:The human protein Siderocalin (Scn) inhibits bacterial iron acquisition by binding catechol siderophores. Several pathogenic bacteria respond by making stealth siderophores that are not recognized by Scn. Fluvibactin and vibriobactin, respectively of Vibrio fluvialis and Vibrio cholerae, include an oxazoline adjacent to a catechol. This chelating unit binds iron either in a catecholate or a phenolate-oxazoline coordination mode. The latter has been suggested to make vibriobactin a stealth siderophore without directly identifying the coordination mode in relation to Scn binding. We use Scn binding assays with the two siderophores and two oxazoline-substituted analogs and the crystal structure of Fe-fluvibactin:Scn to show that the oxazoline does not prevent Scn binding; hence, vibriobactin is not a stealth siderophore. We show that the phenolate-oxazoline coordination mode is present at physiological pH and is not bound by Scn. However, Scn binding shifts the coordination to the catecholate mode and thereby inactivates this siderophore
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immune interference in mycobacterium tuberculosis intracellular iron acquisition through Siderocalin recognition of carboxymycobactins
ACS Chemical Biology, 2011Co-Authors: Trisha M Hoette, Matthew C. Clifton, Roland K. Strong, Anna M Zawadzka, Meg Holmes, Kenneth N. RaymondAbstract:The innate immune system antibacterial protein Siderocalin (Scn) binds ferric carboxymycobactin (CMB) and also several catecholate siderophores. Although the recognition of catecholates by Scn has been thoroughly investigated, the binding interactions of Scn with the full spectrum of CMB isoforms have not been studied. Here we show that Scn uses different binding modes for the limited subset of bound CMB isoforms, resulting in a range of binding affinities that are much weaker than other siderophore targets of Scn. Understanding the binding interaction between Scn and CMBs provides clues for the influence of Scn on mycobacterial iron acquisition.
Roland K. Strong - One of the best experts on this subject based on the ideXlab platform.
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parsing the functional specificity of Siderocalin lipocalin 2 ngal for siderophores and related small molecule ligands
Journal of Structural Biology, 2019Co-Authors: Matthew C. Clifton, Kenneth N. Raymond, Peter B Rupert, Trisha M Hoette, Rebecca J Abergel, Roland K. StrongAbstract:Siderocalin/Lipocalin 2/Neutrophil Gelatinase Associated Lipocalin/24p3 is an innate immune system protein with bacteriostatic activity, acting by tightly binding and sequestering diverse catecholate and mixed-type ferric siderophores from enteric bacteria and mycobacteria. Bacterial virulence achieved through siderophore modifications, or utilization of alternate siderophores, can be explained by evasion of Siderocalin binding. Siderocalin has also been implicated in a wide variety of disease processes, though often in seemingly contradictory ways, and has been proposed to bind to a broader array of ligands beyond siderophores. Using structural, directed mutational, and binding studies, we have sought to rigorously test, and fully elucidate, the Siderocalin recognition mechanism. Several proposed ligands fail to meet rigorous binding criteria, including the bacterial siderophore pyochelin, the iron-chelating catecholamine hormone norepinephrine, and the bacterial second messenger cyclic diguanylate monophosphate. While possessing a remarkably rigid structure, in principle simplifying analyses of ligand recognition, understanding Scn recognition is complicated by the observed conformational and stoichiometric plasticity, and instability, of its bona fide siderophore ligands. Since the role of Siderocalin at the early host/pathogen interface is to compete for bacterial ferric siderophores, we also analyzed how bacterial siderophore binding proteins and enzymes alternately recognize siderophores that efficiently bind to, or evade, Siderocalin sequestration - including determining the crystal structure of Bacillus cereus YfiY bound to schizokinen. These studies combine to refine the potential physiological functions of Siderocalin by defining its multiplexed recognition mechanism.
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Engineered Recognition of Tetravalent Zirconium and Thorium by Chelator–Protein Systems: Toward Flexible Radiotherapy and Imaging Platforms
2016Co-Authors: Ilya Captain, Roland K. Strong, Peter B Rupert, Corie Y Ralston, Gauthier J.-p. Deblonde, Marie-claire Illy, Emeline Rostan, Rebecca J AbergelAbstract:Targeted α therapy holds tremendous potential as a cancer treatment: it offers the possibility of delivering a highly cytotoxic dose to targeted cells while minimizing damage to surrounding healthy tissue. The metallic α-generating radioisotopes 225Ac and 227Th are promising radionuclides for therapeutic use, provided adequate chelation and targeting. Here we demonstrate a new chelating platform composed of a multidentate high-affinity oxygen-donating ligand 3,4,3-LI(CAM) bound to the mammalian protein Siderocalin. Respective stability constants log β110 = 29.65 ± 0.65, 57.26 ± 0.20, and 47.71 ± 0.08, determined for the EuIII (a lanthanide surrogate for AcIII), ZrIV, and ThIV complexes of 3,4,3-LI(CAM) through spectrophotometric titrations, reveal this ligand to be one of the most powerful chelators for both trivalent and tetravalent metal ions at physiological pH. The resulting metal–ligand complexes are also recognized with extremely high affinity by the siderophore-binding protein Siderocalin, with dissociation constants below 40 nM and tight electrostatic interactions, as evidenced by X-ray structures of the protein:ligand:metal adducts with ZrIV and ThIV. Finally, differences in biodistribution profiles between free and Siderocalin-bound 238PuIV-3,4,3-LI(CAM) complexes confirm in vivo stability of the protein construct. The Siderocalin:3,4,3-LI(CAM) assembly can therefore serve as a “lock” to consolidate binding to the therapeutic 225Ac and 227Th isotopes or to the positron emission tomography emitter 89Zr, independent of metal valence state
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Siderocalin mediated recognition sensitization and cellular uptake of actinides
Proceedings of the National Academy of Sciences of the United States of America, 2015Co-Authors: Benjamin E Allred, Roland K. Strong, Peter B Rupert, Stacey Gauny, Corie Y Ralston, Manuel Sturzbecherhoehne, Rebecca J AbergelAbstract:Synthetic radionuclides, such as the transuranic actinides plutonium, americium, and curium, present severe health threats as contaminants, and understanding the scope of the biochemical interactions involved in actinide transport is instrumental in managing human contamination. Here we show that Siderocalin, a mammalian siderophore-binding protein from the lipocalin family, specifically binds lanthanide and actinide complexes through molecular recognition of the ligands chelating the metal ions. Using crystallography, we structurally characterized the resulting Siderocalin-transuranic actinide complexes, providing unprecedented insights into the biological coordination of heavy radioelements. In controlled in vitro assays, we found that intracellular plutonium uptake can occur through Siderocalin-mediated endocytosis. We also demonstrated that Siderocalin can act as a synergistic antenna to sensitize the luminescence of trivalent lanthanide and actinide ions in ternary protein-ligand complexes, dramatically increasing the brightness and efficiency of intramolecular energy transfer processes that give rise to metal luminescence. Our results identify Siderocalin as a potential player in the biological trafficking of f elements, but through a secondary ligand-based metal sequestration mechanism. Beyond elucidating contamination pathways, this work is a starting point for the design of two-stage biomimetic platforms for photoluminescence, separation, and transport applications.
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Siderocalin outwits the coordination chemistry of vibriobactin a siderophore of vibrio cholerae
ACS Chemical Biology, 2013Co-Authors: Benjamin E Allred, Matthew C. Clifton, Roland K. Strong, Colin Correnti, Kenneth N. RaymondAbstract:The human protein Siderocalin (Scn) inhibits bacterial iron acquisition by binding catechol siderophores. Several pathogenic bacteria respond by making stealth siderophores that are not recognized by Scn. Fluvibactin and vibriobactin, respectively of Vibrio fluvialis and Vibrio cholerae, include an oxazoline adjacent to a catechol. This chelating unit binds iron either in a catecholate or a phenolate-oxazoline coordination mode. The latter has been suggested to make vibriobactin a stealth siderophore without directly identifying the coordination mode in relation to Scn binding. We use Scn binding assays with the two siderophores and two oxazoline-substituted analogs and the crystal structure of Fe-fluvibactin:Scn to show that the oxazoline does not prevent Scn binding; hence, vibriobactin is not a stealth siderophore. We show that the phenolate-oxazoline coordination mode is present at physiological pH and is not bound by Scn. However, Scn binding shifts the coordination to the catecholate mode and thereb...
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SPR analyses of Scn-peptide fusions.
2013Co-Authors: Kathryn A. K. Finton, Colin Correnti, Peter B Rupert, Kevin Larimore, Benjamin H. Larman, Della Friend, Stephen J. Elledge, Philip D. Greenberg, Roland K. StrongAbstract:(A) The generalized Siderocalin fusion construct used for PhIP-Seq peptide expression is shown. (B) Corrected and normalized SPR responses for 4E10 IgG binding to the top five peptides immobilized on a CM5 biosensor chip are plotted. (C) Corrected and normalized SPR responses of 4E10 IgG (300 nM; duplicate runs) binding to peptides (colored as in (B)) at 500 mM NaCl are plotted; inset shows magnified view. Normalized SPR responses are plotted in arbitrary units.
Matthew C. Clifton - One of the best experts on this subject based on the ideXlab platform.
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parsing the functional specificity of Siderocalin lipocalin 2 ngal for siderophores and related small molecule ligands
Journal of Structural Biology, 2019Co-Authors: Matthew C. Clifton, Kenneth N. Raymond, Peter B Rupert, Trisha M Hoette, Rebecca J Abergel, Roland K. StrongAbstract:Siderocalin/Lipocalin 2/Neutrophil Gelatinase Associated Lipocalin/24p3 is an innate immune system protein with bacteriostatic activity, acting by tightly binding and sequestering diverse catecholate and mixed-type ferric siderophores from enteric bacteria and mycobacteria. Bacterial virulence achieved through siderophore modifications, or utilization of alternate siderophores, can be explained by evasion of Siderocalin binding. Siderocalin has also been implicated in a wide variety of disease processes, though often in seemingly contradictory ways, and has been proposed to bind to a broader array of ligands beyond siderophores. Using structural, directed mutational, and binding studies, we have sought to rigorously test, and fully elucidate, the Siderocalin recognition mechanism. Several proposed ligands fail to meet rigorous binding criteria, including the bacterial siderophore pyochelin, the iron-chelating catecholamine hormone norepinephrine, and the bacterial second messenger cyclic diguanylate monophosphate. While possessing a remarkably rigid structure, in principle simplifying analyses of ligand recognition, understanding Scn recognition is complicated by the observed conformational and stoichiometric plasticity, and instability, of its bona fide siderophore ligands. Since the role of Siderocalin at the early host/pathogen interface is to compete for bacterial ferric siderophores, we also analyzed how bacterial siderophore binding proteins and enzymes alternately recognize siderophores that efficiently bind to, or evade, Siderocalin sequestration - including determining the crystal structure of Bacillus cereus YfiY bound to schizokinen. These studies combine to refine the potential physiological functions of Siderocalin by defining its multiplexed recognition mechanism.
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Siderocalin/Lcn2/NGAL/24p3 Does Not Drive Apoptosis Through Gentisic Acid Mediated Iron Withdrawal in
2016Co-Authors: Hematopoietic Cell Lines, Matthew C. Clifton, Colin Correnti, Vera Richardson, Allyson K Sia, Mario Ruiz, Margaret A Holmes, Ashok D. B, Suryo Rahmanto, Brett K KaiserAbstract:Siderocalin (also lipocalin 2, NGAL or 24p3) binds iron as complexes with specific siderophores, which are low molecular weight, ferric ion-specific chelators. In innate immunity, Siderocalin slows the growth of infecting bacteria by sequestering bacterial ferric siderophores. Siderocalin also binds simple catechols, which can serve as siderophores in the damaged urinary tract. Siderocalin has also been proposed to alter cellular iron trafficking, for instance, driving apoptosis through iron efflux via BOCT. An endogenous siderophore composed of gentisic acid (2,5-dihydroxybenzoic acid) substituents was proposed to mediate cellular efflux. However, binding studies reported herein contradict the proposal that gentisic acid forms high-affinity ternary complexes with Siderocalin and iron, or that gentisic acid can serve as an endogenous siderophore at neutral pH. We also demonstrate that Siderocalin does not induce cellular iron efflux or stimulate apoptosis
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Siderocalin outwits the coordination chemistry of vibriobactin a siderophore of vibrio cholerae
ACS Chemical Biology, 2013Co-Authors: Benjamin E Allred, Matthew C. Clifton, Roland K. Strong, Colin Correnti, Kenneth N. RaymondAbstract:The human protein Siderocalin (Scn) inhibits bacterial iron acquisition by binding catechol siderophores. Several pathogenic bacteria respond by making stealth siderophores that are not recognized by Scn. Fluvibactin and vibriobactin, respectively of Vibrio fluvialis and Vibrio cholerae, include an oxazoline adjacent to a catechol. This chelating unit binds iron either in a catecholate or a phenolate-oxazoline coordination mode. The latter has been suggested to make vibriobactin a stealth siderophore without directly identifying the coordination mode in relation to Scn binding. We use Scn binding assays with the two siderophores and two oxazoline-substituted analogs and the crystal structure of Fe-fluvibactin:Scn to show that the oxazoline does not prevent Scn binding; hence, vibriobactin is not a stealth siderophore. We show that the phenolate-oxazoline coordination mode is present at physiological pH and is not bound by Scn. However, Scn binding shifts the coordination to the catecholate mode and thereb...
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Siderocalin Outwits the Coordination Chemistry of Vibriobactin, a Siderophore of Vibrio cholerae
2013Co-Authors: Benjamin E. Allred, Matthew C. Clifton, Roland K. Strong, Colin Correnti, Kenneth N. RaymondAbstract:The human protein Siderocalin (Scn) inhibits bacterial iron acquisition by binding catechol siderophores. Several pathogenic bacteria respond by making stealth siderophores that are not recognized by Scn. Fluvibactin and vibriobactin, respectively of Vibrio fluvialis and Vibrio cholerae, include an oxazoline adjacent to a catechol. This chelating unit binds iron either in a catecholate or a phenolate-oxazoline coordination mode. The latter has been suggested to make vibriobactin a stealth siderophore without directly identifying the coordination mode in relation to Scn binding. We use Scn binding assays with the two siderophores and two oxazoline-substituted analogs and the crystal structure of Fe-fluvibactin:Scn to show that the oxazoline does not prevent Scn binding; hence, vibriobactin is not a stealth siderophore. We show that the phenolate-oxazoline coordination mode is present at physiological pH and is not bound by Scn. However, Scn binding shifts the coordination to the catecholate mode and thereby inactivates this siderophore
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Siderocalin lcn2 ngal 24p3 does not drive apoptosis through gentisic acid mediated iron withdrawal in hematopoietic cell lines
PLOS ONE, 2012Co-Authors: Colin Correnti, Matthew C. Clifton, Vera Richardson, Allyson K Sia, Ashok D Bandaranayake, Mario Ruiz, Yohan Suryo Rahmanto, žaklina Kovacevic, Margaret A Holmes, Brett K KaiserAbstract:Siderocalin (also lipocalin 2, NGAL or 24p3) binds iron as complexes with specific siderophores, which are low molecular weight, ferric ion-specific chelators. In innate immunity, Siderocalin slows the growth of infecting bacteria by sequestering bacterial ferric siderophores. Siderocalin also binds simple catechols, which can serve as siderophores in the damaged urinary tract. Siderocalin has also been proposed to alter cellular iron trafficking, for instance, driving apoptosis through iron efflux via BOCT. An endogenous siderophore composed of gentisic acid (2,5-dihydroxybenzoic acid) substituents was proposed to mediate cellular efflux. However, binding studies reported herein contradict the proposal that gentisic acid forms high-affinity ternary complexes with Siderocalin and iron, or that gentisic acid can serve as an endogenous siderophore at neutral pH. We also demonstrate that Siderocalin does not induce cellular iron efflux or stimulate apoptosis, questioning the role Siderocalin plays in modulating iron metabolism.
Rebecca J Abergel - One of the best experts on this subject based on the ideXlab platform.
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parsing the functional specificity of Siderocalin lipocalin 2 ngal for siderophores and related small molecule ligands
Journal of Structural Biology, 2019Co-Authors: Matthew C. Clifton, Kenneth N. Raymond, Peter B Rupert, Trisha M Hoette, Rebecca J Abergel, Roland K. StrongAbstract:Siderocalin/Lipocalin 2/Neutrophil Gelatinase Associated Lipocalin/24p3 is an innate immune system protein with bacteriostatic activity, acting by tightly binding and sequestering diverse catecholate and mixed-type ferric siderophores from enteric bacteria and mycobacteria. Bacterial virulence achieved through siderophore modifications, or utilization of alternate siderophores, can be explained by evasion of Siderocalin binding. Siderocalin has also been implicated in a wide variety of disease processes, though often in seemingly contradictory ways, and has been proposed to bind to a broader array of ligands beyond siderophores. Using structural, directed mutational, and binding studies, we have sought to rigorously test, and fully elucidate, the Siderocalin recognition mechanism. Several proposed ligands fail to meet rigorous binding criteria, including the bacterial siderophore pyochelin, the iron-chelating catecholamine hormone norepinephrine, and the bacterial second messenger cyclic diguanylate monophosphate. While possessing a remarkably rigid structure, in principle simplifying analyses of ligand recognition, understanding Scn recognition is complicated by the observed conformational and stoichiometric plasticity, and instability, of its bona fide siderophore ligands. Since the role of Siderocalin at the early host/pathogen interface is to compete for bacterial ferric siderophores, we also analyzed how bacterial siderophore binding proteins and enzymes alternately recognize siderophores that efficiently bind to, or evade, Siderocalin sequestration - including determining the crystal structure of Bacillus cereus YfiY bound to schizokinen. These studies combine to refine the potential physiological functions of Siderocalin by defining its multiplexed recognition mechanism.
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Engineered Recognition of Tetravalent Zirconium and Thorium by Chelator–Protein Systems: Toward Flexible Radiotherapy and Imaging Platforms
2016Co-Authors: Ilya Captain, Roland K. Strong, Peter B Rupert, Corie Y Ralston, Gauthier J.-p. Deblonde, Marie-claire Illy, Emeline Rostan, Rebecca J AbergelAbstract:Targeted α therapy holds tremendous potential as a cancer treatment: it offers the possibility of delivering a highly cytotoxic dose to targeted cells while minimizing damage to surrounding healthy tissue. The metallic α-generating radioisotopes 225Ac and 227Th are promising radionuclides for therapeutic use, provided adequate chelation and targeting. Here we demonstrate a new chelating platform composed of a multidentate high-affinity oxygen-donating ligand 3,4,3-LI(CAM) bound to the mammalian protein Siderocalin. Respective stability constants log β110 = 29.65 ± 0.65, 57.26 ± 0.20, and 47.71 ± 0.08, determined for the EuIII (a lanthanide surrogate for AcIII), ZrIV, and ThIV complexes of 3,4,3-LI(CAM) through spectrophotometric titrations, reveal this ligand to be one of the most powerful chelators for both trivalent and tetravalent metal ions at physiological pH. The resulting metal–ligand complexes are also recognized with extremely high affinity by the siderophore-binding protein Siderocalin, with dissociation constants below 40 nM and tight electrostatic interactions, as evidenced by X-ray structures of the protein:ligand:metal adducts with ZrIV and ThIV. Finally, differences in biodistribution profiles between free and Siderocalin-bound 238PuIV-3,4,3-LI(CAM) complexes confirm in vivo stability of the protein construct. The Siderocalin:3,4,3-LI(CAM) assembly can therefore serve as a “lock” to consolidate binding to the therapeutic 225Ac and 227Th isotopes or to the positron emission tomography emitter 89Zr, independent of metal valence state
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Siderocalin mediated recognition sensitization and cellular uptake of actinides
Proceedings of the National Academy of Sciences of the United States of America, 2015Co-Authors: Benjamin E Allred, Roland K. Strong, Peter B Rupert, Stacey Gauny, Corie Y Ralston, Manuel Sturzbecherhoehne, Rebecca J AbergelAbstract:Synthetic radionuclides, such as the transuranic actinides plutonium, americium, and curium, present severe health threats as contaminants, and understanding the scope of the biochemical interactions involved in actinide transport is instrumental in managing human contamination. Here we show that Siderocalin, a mammalian siderophore-binding protein from the lipocalin family, specifically binds lanthanide and actinide complexes through molecular recognition of the ligands chelating the metal ions. Using crystallography, we structurally characterized the resulting Siderocalin-transuranic actinide complexes, providing unprecedented insights into the biological coordination of heavy radioelements. In controlled in vitro assays, we found that intracellular plutonium uptake can occur through Siderocalin-mediated endocytosis. We also demonstrated that Siderocalin can act as a synergistic antenna to sensitize the luminescence of trivalent lanthanide and actinide ions in ternary protein-ligand complexes, dramatically increasing the brightness and efficiency of intramolecular energy transfer processes that give rise to metal luminescence. Our results identify Siderocalin as a potential player in the biological trafficking of f elements, but through a secondary ligand-based metal sequestration mechanism. Beyond elucidating contamination pathways, this work is a starting point for the design of two-stage biomimetic platforms for photoluminescence, separation, and transport applications.
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galline ex fabp is an antibacterial Siderocalin and a lysophosphatidic acid sensor functioning through dual ligand specificities
Structure, 2011Co-Authors: Colin Correnti, Matthew C. Clifton, Kenneth N. Raymond, Trisha M Hoette, Rebecca J Abergel, Mario Ruiz, Ben Allred, Ranieri Cancedda, Fiorella Descalzi, Roland K. StrongAbstract:Galline Ex-FABP was identified as another candidate antibacterial, catecholate siderophore binding lipocalin (Siderocalin) based on structural parallels with the family archetype, mammalian Siderocalin. Binding assays show that Ex-FABP retains iron in a siderophore-dependent manner in both hypertrophic and dedifferentiated chondrocytes, where Ex-FABP expression is induced after treatment with proinflammatory agents, and specifically binds ferric complexes of enterobactin, parabactin, bacillibactin and, unexpectedly, monoglucosylated enterobactin, which does not bind to Siderocalin. Growth arrest assays functionally confirm the bacteriostatic effect of Ex-FABP in vitro under iron-limiting conditions. The 1.8 A crystal structure of Ex-FABP explains the expanded specificity, but also surprisingly reveals an extended, multi-chambered cavity extending through the protein and encompassing two separate ligand specificities, one for bacterial siderophores (as in Siderocalin) at one end and one specifically binding copurified lysophosphatidic acid, a potent cell signaling molecule, at the other end, suggesting Ex-FABP employs dual functionalities to explain its diverse endogenous activities.
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the role of electrostatics in siderophore recognition by the immunoprotein Siderocalin
Journal of the American Chemical Society, 2008Co-Authors: Trisha M Hoette, Roland K. Strong, Rebecca J Abergel, Kenneth N. RaymondAbstract:Iron is required for virulence of most bacterial pathogens, many of which rely on siderophores, small-molecule chelators, to scavenge iron in mammalian hosts. As an immune response, the human protein Siderocalin binds both apo and ferric siderophores in order to intercept delivery of iron to the bacterium, impeding virulence. The introduction of steric clashes into the siderophore structure is an important mechanism of evading sequestration. However, in the absence of steric incompatibilities, electrostatic interactions determine siderophore strength of binding by Siderocalin. By using a series of isosteric enterobactin analogues, the contribution of electrostatic interactions, including both charge−charge and cation−π, to the recognition of 2,3-catecholate siderophores has been deconvoluted. The analogues used in the study incorporate a systematic combination of 2,3-catecholamide (CAM) and N-hydroxypyridinonate (1,2-HOPO) binding units on a tris(2-aminoethyl)amine (tren) backbone, [tren(CAM)m(1,2-HOPO)n,...
Colin Correnti - One of the best experts on this subject based on the ideXlab platform.
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Siderocalin/Lcn2/NGAL/24p3 Does Not Drive Apoptosis Through Gentisic Acid Mediated Iron Withdrawal in
2016Co-Authors: Hematopoietic Cell Lines, Matthew C. Clifton, Colin Correnti, Vera Richardson, Allyson K Sia, Mario Ruiz, Margaret A Holmes, Ashok D. B, Suryo Rahmanto, Brett K KaiserAbstract:Siderocalin (also lipocalin 2, NGAL or 24p3) binds iron as complexes with specific siderophores, which are low molecular weight, ferric ion-specific chelators. In innate immunity, Siderocalin slows the growth of infecting bacteria by sequestering bacterial ferric siderophores. Siderocalin also binds simple catechols, which can serve as siderophores in the damaged urinary tract. Siderocalin has also been proposed to alter cellular iron trafficking, for instance, driving apoptosis through iron efflux via BOCT. An endogenous siderophore composed of gentisic acid (2,5-dihydroxybenzoic acid) substituents was proposed to mediate cellular efflux. However, binding studies reported herein contradict the proposal that gentisic acid forms high-affinity ternary complexes with Siderocalin and iron, or that gentisic acid can serve as an endogenous siderophore at neutral pH. We also demonstrate that Siderocalin does not induce cellular iron efflux or stimulate apoptosis
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Siderocalin outwits the coordination chemistry of vibriobactin a siderophore of vibrio cholerae
ACS Chemical Biology, 2013Co-Authors: Benjamin E Allred, Matthew C. Clifton, Roland K. Strong, Colin Correnti, Kenneth N. RaymondAbstract:The human protein Siderocalin (Scn) inhibits bacterial iron acquisition by binding catechol siderophores. Several pathogenic bacteria respond by making stealth siderophores that are not recognized by Scn. Fluvibactin and vibriobactin, respectively of Vibrio fluvialis and Vibrio cholerae, include an oxazoline adjacent to a catechol. This chelating unit binds iron either in a catecholate or a phenolate-oxazoline coordination mode. The latter has been suggested to make vibriobactin a stealth siderophore without directly identifying the coordination mode in relation to Scn binding. We use Scn binding assays with the two siderophores and two oxazoline-substituted analogs and the crystal structure of Fe-fluvibactin:Scn to show that the oxazoline does not prevent Scn binding; hence, vibriobactin is not a stealth siderophore. We show that the phenolate-oxazoline coordination mode is present at physiological pH and is not bound by Scn. However, Scn binding shifts the coordination to the catecholate mode and thereb...
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SPR analyses of Scn-peptide fusions.
2013Co-Authors: Kathryn A. K. Finton, Colin Correnti, Peter B Rupert, Kevin Larimore, Benjamin H. Larman, Della Friend, Stephen J. Elledge, Philip D. Greenberg, Roland K. StrongAbstract:(A) The generalized Siderocalin fusion construct used for PhIP-Seq peptide expression is shown. (B) Corrected and normalized SPR responses for 4E10 IgG binding to the top five peptides immobilized on a CM5 biosensor chip are plotted. (C) Corrected and normalized SPR responses of 4E10 IgG (300 nM; duplicate runs) binding to peptides (colored as in (B)) at 500 mM NaCl are plotted; inset shows magnified view. Normalized SPR responses are plotted in arbitrary units.
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Siderocalin Outwits the Coordination Chemistry of Vibriobactin, a Siderophore of Vibrio cholerae
2013Co-Authors: Benjamin E. Allred, Matthew C. Clifton, Roland K. Strong, Colin Correnti, Kenneth N. RaymondAbstract:The human protein Siderocalin (Scn) inhibits bacterial iron acquisition by binding catechol siderophores. Several pathogenic bacteria respond by making stealth siderophores that are not recognized by Scn. Fluvibactin and vibriobactin, respectively of Vibrio fluvialis and Vibrio cholerae, include an oxazoline adjacent to a catechol. This chelating unit binds iron either in a catecholate or a phenolate-oxazoline coordination mode. The latter has been suggested to make vibriobactin a stealth siderophore without directly identifying the coordination mode in relation to Scn binding. We use Scn binding assays with the two siderophores and two oxazoline-substituted analogs and the crystal structure of Fe-fluvibactin:Scn to show that the oxazoline does not prevent Scn binding; hence, vibriobactin is not a stealth siderophore. We show that the phenolate-oxazoline coordination mode is present at physiological pH and is not bound by Scn. However, Scn binding shifts the coordination to the catecholate mode and thereby inactivates this siderophore
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Siderocalin lcn2 ngal 24p3 does not drive apoptosis through gentisic acid mediated iron withdrawal in hematopoietic cell lines
PLOS ONE, 2012Co-Authors: Colin Correnti, Matthew C. Clifton, Vera Richardson, Allyson K Sia, Ashok D Bandaranayake, Mario Ruiz, Yohan Suryo Rahmanto, žaklina Kovacevic, Margaret A Holmes, Brett K KaiserAbstract:Siderocalin (also lipocalin 2, NGAL or 24p3) binds iron as complexes with specific siderophores, which are low molecular weight, ferric ion-specific chelators. In innate immunity, Siderocalin slows the growth of infecting bacteria by sequestering bacterial ferric siderophores. Siderocalin also binds simple catechols, which can serve as siderophores in the damaged urinary tract. Siderocalin has also been proposed to alter cellular iron trafficking, for instance, driving apoptosis through iron efflux via BOCT. An endogenous siderophore composed of gentisic acid (2,5-dihydroxybenzoic acid) substituents was proposed to mediate cellular efflux. However, binding studies reported herein contradict the proposal that gentisic acid forms high-affinity ternary complexes with Siderocalin and iron, or that gentisic acid can serve as an endogenous siderophore at neutral pH. We also demonstrate that Siderocalin does not induce cellular iron efflux or stimulate apoptosis, questioning the role Siderocalin plays in modulating iron metabolism.