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Laisney J, Chevallet M, Fauquant C, Sageot C, Moreau Y, Predoi D, Herlin-Boime N, Lebrun C, Michaud-Soret I. Ligand-Promoted Surface Solubilization of TiO 2 Nanoparticles by the Enterobactin Siderophore in Biological Medium. Biomolecules 2022; 12:1516. [PMID: 36291725 PMCID: PMC9599204 DOI: 10.3390/biom12101516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 10/03/2022] [Accepted: 10/10/2022] [Indexed: 03/08/2024] Open
Abstract
Titanium dioxide nanoparticles (TiO2-NPs) are increasingly used in consumer products for their particular properties. Even though TiO2 is considered chemically stable and insoluble, studying their behavior in biological environments is of great importance to figure their potential dissolution and transformation. The interaction between TiO2-NPs with different sizes and crystallographic forms (anatase and rutile) and the strong chelating enterobactin (ent) siderophore was investigated to look at a possible dissolution. For the first time, direct evidence of anatase TiO2-NP surface dissolution or solubilization (i.e., the removal of Ti atoms located at the surface) in a biological medium by this siderophore was shown and the progressive formation of a hexacoordinated titanium-enterobactin (Ti-ent) complex observed. This complex was characterized by UV-visible and Fourier transform infrared (FTIR) spectroscopy (both supported by Density Functional Theory calculations) as well as electrospray ionization mass spectrometry (ESI-MS) and X-ray photoelectron spectroscopy (XPS). A maximum of ca. 6.3% of Ti surface atoms were found to be solubilized after 24 h of incubation, releasing Ti-ent complexes in the micromolar range that could then be taken up by bacteria in an iron-depleted medium. From a health and environmental point of view, the effects associated to the solubilization of the E171 TiO2 food additive in the presence of enterobactin and the entrance of the Ti-enterobactin complex in bacteria were questioned.
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Affiliation(s)
- Jérôme Laisney
- Université Grenoble Alpes, CNRS CEA, IRIG-LCBM, 38000 Grenoble, France
| | | | - Caroline Fauquant
- Université Grenoble Alpes, CNRS CEA, IRIG-LCBM, 38000 Grenoble, France
| | - Camille Sageot
- Université Grenoble Alpes, CNRS CEA, IRIG-LCBM, 38000 Grenoble, France
| | - Yohann Moreau
- Université Grenoble Alpes, CNRS CEA, IRIG-LCBM, 38000 Grenoble, France
| | - Daniela Predoi
- National Institute of Materials Physics, Atomistilor 105 bis, 077125 Magurele, Romania
| | | | - Colette Lebrun
- Université Grenoble Alpes, IRIG-SyMMES, CEA, CNRS, CEA-Grenoble, 38000 Grenoble, France
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Gigant B, Landrieu I, Fauquant C, Barbier P, Huvent I, Wieruszeski JM, Knossow M, Lippens G. Mechanism of Tau-promoted microtubule assembly as probed by NMR spectroscopy. J Am Chem Soc 2014; 136:12615-23. [PMID: 25162583 DOI: 10.1021/ja504864m] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Determining the molecular mechanism of the neuronal Tau protein in the tubulin heterodimer assembly has been a challenge owing to the dynamic character of the complex and the large size of microtubules. We use here defined constructs comprising one or two tubulin heterodimers to characterize their association with a functional fragment of Tau, named TauF4. TauF4 binds with high affinities to the tubulin heterodimer complexes, but NMR spectroscopy shows that it remains highly dynamic, partly because of the interaction with the acidic C-terminal tails of the tubulin monomers. When bound to a single tubulin heterodimer, TauF4 is characterized by an overhanging peptide corresponding to the first of the four microtubule binding repeats of Tau. This peptide becomes immobilized in the complex with two longitudinally associated tubulin heterodimers. The longitudinal associations are favored by the fragment and contribute to Tau's functional role in microtubule assembly.
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Affiliation(s)
- Benoît Gigant
- Laboratoire d'Enzymologie et Biochimie Structurales, Centre de Recherche de Gif, Centre National de la Recherche Scientifique , 91198 Gif sur Yvette, France
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Cuillel M, Chevallet M, Charbonnier P, Fauquant C, Pignot-Paintrand I, Arnaud J, Cassio D, Michaud-Soret I, Mintz E. Interference of CuO nanoparticles with metal homeostasis in hepatocytes under sub-toxic conditions. Nanoscale 2014; 6:1707-1715. [PMID: 24343273 DOI: 10.1039/c3nr05041f] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Copper oxide nanoparticles (CuO-NP) were studied for their toxicity and mechanism of action on hepatocytes (HepG2), in relation to Cu homeostasis disruption. Indeed, hepatocytes, in the liver, are responsible for the whole body Cu balance and should be a major line of defence in the case of exposure to CuO-NP. We investigated the early responses to sub-toxic doses of CuO-NP and compared them to equivalent doses of Cu added as salt to see if there is a specific nano-effect related to Cu homeostasis in hepatocytes. The expression of the genes encoding the Cu-ATPase ATP7B, metallothionein 1X, heme oxygenase 1, heat shock protein 70, superoxide dismutase 1, glutamate cysteine ligase modifier subunit, metal responsive element-binding transcription factor 1 and zinc transporter 1 was analyzed by qRT-PCR. These genes are known to be involved in response to Cu, Zn and/or oxidative stresses. Except for MTF1, ATP7B and SOD1, we clearly observed an up regulation of these genes expression in CuO-NP treated cells, as compared to CuCl2. In addition, ATP7B trafficking from the Golgi network to the bile canaliculus membrane was observed in WIF-B9 cells, showing a need for Cu detoxification. This shows an increase in the intracellular Cu concentration, probably due to Cu release from endosomal CuO-NP solubilisation. Our data show that CuO-NP enter hepatic cells, most probably by endocytosis, bypassing the cellular defence mechanism against Cu, thus acting as a Trojan horse. Altogether, this study suggests that sub-toxic CuO-NP treatments induce successively a Cu overload, a Cu-Zn exchange on metallothioneins and MTF1 regulation on both Cu and Zn homeostasis.
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Sibille N, Huvent I, Fauquant C, Verdegem D, Amniai L, Leroy A, Wieruszeski JM, Lippens G, Landrieu I. Structural characterization by nuclear magnetic resonance of the impact of phosphorylation in the proline-rich region of the disordered Tau protein. Proteins 2011; 80:454-62. [PMID: 22072628 DOI: 10.1002/prot.23210] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 09/22/2011] [Accepted: 09/23/2011] [Indexed: 11/10/2022]
Abstract
Phosphorylation of the neuronal Tau protein is implicated in both the regulation of its physiological function of microtubule stabilization and its pathological propensity to aggregate into the fibers that characterize Alzheimer's diseased neurons. However, how specific phosphorylation events influence both aspects of Tau biology remains largely unknown. In this study, we address the structural impact of phosphorylation of the Tau protein by Nuclear Magnetic Resonance (NMR) spectroscopy on a functional fragment of Tau (Tau[Ser208-Ser324] = TauF4). TauF4 was phosphorylated by the proline-directed CDK2/CycA3 kinase on Thr231 (generating the AT180 epitope), Ser235, and equally on Thr212 and Thr217 in the Proline-rich region (Tau[Ser208-Gln244] or PRR). These modifications strongly decrease the capacity of TauF4 to polymerize tubulin into microtubules. While all the NMR parameters are consistent with a globally disordered Tau protein fragment, local clusters of structuration can be defined. The most salient result of our NMR analysis is that phosphorylation in the PRR stabilizes a short α-helix that runs from pSer235 till the very beginning of the microtubule-binding region (Tau[Thr245-Ser324] or MTBR of TauF4). Phosphorylation of Thr231/Ser235 creates a N-cap with helix stabilizing role while phosphorylation of Thr212/Thr217 does not induce modification of the local transient secondary structure, showing that the stabilizing effect is sequence specific. Using paramagnetic relaxation experiments, we additionally show a transient interaction between the PRR and the MTBR, observed in both TauF4 and phospho-TauF4.
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Affiliation(s)
- Nathalie Sibille
- CNRS-UMR 8576 UGSF-IFR 147, Université des Sciences et Technologies de Lille 1, 59655 Villeneuve d'Ascq Cedex, France
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Fauquant C, Redeker V, Landrieu I, Wieruszeski JM, Verdegem D, Laprévote O, Lippens G, Gigant B, Knossow M. Systematic identification of tubulin-interacting fragments of the microtubule-associated protein Tau leads to a highly efficient promoter of microtubule assembly. J Biol Chem 2011; 286:33358-68. [PMID: 21757739 DOI: 10.1074/jbc.m111.223545] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Tau is a microtubule-associated protein that stabilizes microtubules and stimulates their assembly. Current descriptions of the tubulin-interacting regions of Tau involve microtubules as the target and result mainly from deletions of Tau domains based on sequence analysis and from NMR spectroscopy experiments. Here, instead of microtubules, we use the complex of two tubulin heterodimers with the stathmin-like domain of the RB3 protein (T(2)R) to identify interacting Tau fragments generated by limited proteolysis. We show that fragments in the proline-rich region and in the microtubule-binding repeats domain each interact on their own not only with T(2)R but also with microtubules, albeit with moderate affinity. NMR analysis of the interaction with T(2)R of constructs in these two regions leads to a fragment, composed of adjacent parts of the microtubule-binding repeat domain and of the proline-rich region, that binds tightly to stabilized microtubules. This demonstrates the synergy of the two Tau regions we identified in the Tau-microtubule interaction. Moreover, we show that this fragment, which binds to two tubulin heterodimers, stimulates efficiently microtubule assembly.
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Affiliation(s)
- Caroline Fauquant
- Laboratoire d'Enzymologie et Biochimie Structurales, Centre de Recherche de Gif, CNRS, 91198 Gif-sur-Yvette, France
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Dian C, Vitale S, Leonard GA, Bahlawane C, Fauquant C, Leduc D, Muller C, de Reuse H, Michaud-Soret I, Terradot L. The structure of the Helicobacter pylori ferric uptake regulator Fur reveals three functional metal binding sites. Mol Microbiol 2011; 79:1260-75. [PMID: 21208302 DOI: 10.1111/j.1365-2958.2010.07517.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Fur, the ferric uptake regulator, is a transcription factor that controls iron metabolism in bacteria. Binding of ferrous iron to Fur triggers a conformational change that activates the protein for binding to specific DNA sequences named Fur boxes. In Helicobacter pylori, HpFur is involved in acid response and is important for gastric colonization in model animals. Here we present the crystal structure of a functionally active HpFur mutant (HpFur2M; C78S-C150S) bound to zinc. Although its fold is similar to that of other Fur and Fur-like proteins, the crystal structure of HpFur reveals a unique structured N-terminal extension and an unusual C-terminal helix. The structure also shows three metal binding sites: S1 the structural ZnS₄ site previously characterized biochemically in HpFur and the two zinc sites identified in other Fur proteins. Site-directed mutagenesis and spectroscopy analyses of purified wild-type HpFur and various mutants show that the two metal binding sites common to other Fur proteins can be also metallated by cobalt. DNA protection and circular dichroism experiments demonstrate that, while these two sites influence the affinity of HpFur for DNA, only one is absolutely required for DNA binding and could be responsible for the conformational changes of Fur upon metal binding while the other is a secondary site.
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Affiliation(s)
- Cyril Dian
- Structural Biology Group, European Synchrotron Radiation Facility, BP 220 F-38043 Grenoble cedex 9, France
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Bahlawane C, Dian C, Muller C, Round A, Fauquant C, Schauer K, de Reuse H, Terradot L, Michaud-Soret I. Structural and mechanistic insights into Helicobacter pylori NikR activation. Nucleic Acids Res 2010; 38:3106-18. [PMID: 20089510 PMCID: PMC2875016 DOI: 10.1093/nar/gkp1216] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
NikR is a transcriptional metalloregulator central in the mandatory response to acidity of Helicobacter pylori that controls the expression of numerous genes by binding to specific promoter regions. NikR/DNA interactions were proposed to rely on protein activation by Ni(II) binding to high-affinity (HA) and possibly secondary external (X) sites. We describe a biochemical characterization of HpNikR mutants that shows that the HA sites are essential but not sufficient for DNA binding, while the secondary external (X) sites and residues from the HpNikR dimer–dimer interface are important for DNA binding. We show that a second metal is necessary for HpNikR/DNA binding, but only to some promoters. Small-angle X-ray scattering shows that HpNikR adopts a defined conformation in solution, resembling the cis-conformation and suggests that nickel does not trigger large conformational changes in HpNikR. The crystal structures of selected mutants identify the effects of each mutation on HpNikR structure. This study unravels key structural features from which we derive a model for HpNikR activation where: (i) HA sites and an hydrogen bond network are required for DNA binding and (ii) metallation of a unique secondary external site (X) modulates HpNikR DNA binding to low-affinity promoters by disruption of a salt bridge.
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Affiliation(s)
- C Bahlawane
- CNRS UMR 5249 Laboratoire de Chimie et Biologie des Métaux, France
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Vitale S, Fauquant C, Lascoux D, Schauer K, Saint-Pierre C, Michaud-Soret I. A ZnS4 Structural Zinc Site in the Helicobacter pylori Ferric Uptake Regulator. Biochemistry 2009; 48:5582-91. [DOI: 10.1021/bi9004396] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Sylvia Vitale
- CNRS UMR 5249 Laboratoire de Chimie et Biologie des Métaux, Commissariat à l’Energie Atomique (CEA), Direction des Sciences du Vivant (DSV), l’Institut de Recherches en Technologies et Sciences pour le Vivant (iRTSV), and Université Joseph Fourier, 17 rue des Martyrs, F-38054 Grenoble Cedex 9, France
| | - Caroline Fauquant
- CNRS UMR 5249 Laboratoire de Chimie et Biologie des Métaux, Commissariat à l’Energie Atomique (CEA), Direction des Sciences du Vivant (DSV), l’Institut de Recherches en Technologies et Sciences pour le Vivant (iRTSV), and Université Joseph Fourier, 17 rue des Martyrs, F-38054 Grenoble Cedex 9, France
| | - David Lascoux
- Laboratoire de Spectrométrie de Masse des Protéines, Institut de Biologie Structurale, Jean-Pierre Ebel (UMR 5075 CNRS/CEA/UJF), F-38027 Grenoble Cedex 1, France
| | - Kristine Schauer
- Unité Pathogenèse de Helicobacter, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Christine Saint-Pierre
- Laboratoire des Lésions des Acides Nucléiques, DSM/INAC/Service de Chimie Inorganique et Biologique, UMR E-3 CEA/UJF CNRS FRE 3200, 17 rue des Martyrs, Grenoble F-38054 Cedex 9, France
| | - Isabelle Michaud-Soret
- CNRS UMR 5249 Laboratoire de Chimie et Biologie des Métaux, Commissariat à l’Energie Atomique (CEA), Direction des Sciences du Vivant (DSV), l’Institut de Recherches en Technologies et Sciences pour le Vivant (iRTSV), and Université Joseph Fourier, 17 rue des Martyrs, F-38054 Grenoble Cedex 9, France
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Diederix REM, Fauquant C, Rodrigue A, Mandrand-Berthelot MA, Michaud-Soret I. Sub-micromolar affinity of Escherichia coli NikR for Ni(ii). Chem Commun (Camb) 2008:1813-5. [DOI: 10.1039/b719676h] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Fauquant C, Briard-Bion V, Leconte N, Guichardant M, Michalski MC. Membrane phospholipids and sterols in microfiltered milk fat globules. EUR J LIPID SCI TECH 2007. [DOI: 10.1002/ejlt.200700119] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Fauquant C, Diederix REM, Rodrigue A, Dian C, Kapp U, Terradot L, Mandrand-Berthelot MA, Michaud-Soret I. pH dependent Ni(II) binding and aggregation of Escherichia coli and Helicobacter pylori NikR. Biochimie 2006; 88:1693-705. [PMID: 16930800 DOI: 10.1016/j.biochi.2006.07.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2006] [Accepted: 07/19/2006] [Indexed: 11/30/2022]
Abstract
NikR proteins are bacterial metallo-regulatory transcription factors that control the expression of the nickel uptake system and/or nickel containing enzymes such as urease, and are involved in the acid stress response. Here, a comparative study is reported on NikR from Helicobacter pylori (HpNikR) and Escherichia coli (EcNikR), as well as the Q2E mutant of EcNikR. Most attention was focused on the Ni(II) binding properties of these proteins, as a function of pH. The influence of the pH on the Ni(II) binding and aggregation properties was studied using gel filtration analysis and UV-visible absorption spectroscopy in the presence of an increasing concentration of nickel. Q2E and wt EcNikR are identical in Ni(II) binding but the Q2E mutant is impaired to some extent in DNA-binding. For EcNikR it is shown that between pH 6 and 8, addition of Ni(II) above 1 equiv. induces mass aggregation and precipitation, concomitant with binding of Ni(II) up to a maximum of 5-8 Ni(II) ions per monomer. The Ni(II) site with highest affinity is the well-described square planar site with three histidines and one cysteine ligands. Aggregation is complete in the presence of less than 1 extra equiv. of Ni(II) and aggregation is fully reversible and precipitates are rapidly solubilized by addition of EDTA. The sensitivity of EcNikR to aggregation decreases with decreasing pH, concurrent with histidines being the main ligands of the site responsible for aggregation. HpNikR does not display aggregation except at alkaline pH, where 3 Ni(II) equiv. are needed. The participation of a cluster consisting of surface-exposed histidines present in EcNikR but not in HpNikR, is proposed to be involved in aggregation. Our results on HpNikR are compatible with the crystallographic data and with the ability of this protein to bind more than one nickel.
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Affiliation(s)
- C Fauquant
- Laboratoire de Physicochimie Des Métaux en Biologie, Département Réponse et Dynamique et Cellulaires, CEA-Grenoble, 17, avenue des Martyrs, 38054 Grenoble cedex 9, France
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Fauquant C, Briard V, Leconte N, Michalski MC. Differently sized native milk fat globules separated by microfiltration: fatty acid composition of the milk fat globule membrane and triglyceride core. EUR J LIPID SCI TECH 2005. [DOI: 10.1002/ejlt.200401063] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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