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Husar R, Dumas T, Schlegel ML, Schlegel D, Guillaumont D, Solari PL, Moisy P. X-ray absorption spectroscopy and actinide electrochemistry: a setup dedicated to radioactive samples applied to neptunium chemistry. J Synchrotron Radiat 2022; 29:1-10. [PMID: 34985417 PMCID: PMC8733972 DOI: 10.1107/s1600577521011115] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 10/22/2021] [Indexed: 05/04/2023]
Abstract
A spectroelectrochemical setup has been developed to investigate radioactive elements in small volumes (0.7 to 2 ml) under oxidation-reduction (redox) controlled conditions by X-ray absorption spectroscopy (XAS). The cell design is presented together with in situ XAS measurements performed during neptunium redox reactions. Cycling experiments on the NpO22+/NpO2+ redox couple were applied to qualify the cell electrodynamics using XANES measurements and its ability to probe modifications in the neptunyl hydration shell in a 1 mol l-1 HNO3 solution. The XAS results are in agreement with previous structural studies and the NpO22+/NpO2+ standard potential, determined using Nernst methods, is consistent with measurements based on other techniques. Subsequently, the NpO2+, NpO22+ and Np4+ ion structures in solution were stabilized and measured using EXAFS. The resulting fit parameters are again compared with other results from the literature and with theoretical models in order to evaluate how this spectroelectrochemistry experiment succeeds or fails to stabilize the oxidation states of actinides. The experiment succeeded in: (i) implementing a robust and safe XAS device to investigate unstable radioactive species, (ii) evaluate in a reproducible manner the NpO22+/NpO2+ standard potential under dilute conditions and (iii) clarify mechanistic aspects of the actinyl hydration sphere in solution. In contrast, a detailed comparison of EXAFS fit parameters shows that this method is less appropriate than the majority of the previously reported chemical methods for the stabilization of the Np4+ ion.
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Affiliation(s)
- Richard Husar
- CEA, DES, ISEC, DMRC, Université de Montpellier, Marcoule, France
| | - Thomas Dumas
- CEA, DES, ISEC, DMRC, Université de Montpellier, Marcoule, France
- Correspondence e-mail: ,
| | - Michel L. Schlegel
- CEA, DES-Service d’Etudes Analytiques et de Réactivité des Surfaces (SEARS), CEA, Université Paris-Sacly, 911191 Gif-sur-Yvette, France
- Correspondence e-mail: ,
| | - Daniel Schlegel
- ESTA–École Supérieure des Technologies et des Affaires, 90004 Belfort Cedex, France
| | | | - Pier-Lorenzo Solari
- Synchrotron SOLEIL, L’Orme des Merisiers Saint-Aubin, BP 48, 91192 Gif-sur-Yvette Cedex, France
| | - Philippe Moisy
- CEA, DES, ISEC, DMRC, Université de Montpellier, Marcoule, France
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2
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Ye G, Roques J, Solari PL, Den Auwer C, Jeanson A, Brandel J, Charbonnière LJ, Wu W, Simoni É. Structural and Thermodynamics Studies on Polyaminophosphonate Ligands for Uranyl Decorporation. Inorg Chem 2021; 60:2149-2159. [PMID: 33522798 DOI: 10.1021/acs.inorgchem.0c02145] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The development of actinide decorporation agents with high complexation affinity, high tissue specificity, and low biological toxicity is of vital importance for the sustained and healthy development of nuclear energy. After accidental actinide intake, sequestration by chelation therapy to reduce acute damage is considered as the most effective method. In this work, a series of bis- and tetra-phosphonated pyridine ligands have been designed, synthesized, and characterized for uranyl (UO22+) decorporation. Owing to the absorption of the ligand and the luminescence of the uranyl ion, UV-vis spectroscopy and time-resolved laser-induced fluorescence spectroscopy (TRLFS) were used to probe in situ complexation and structure variation of the complexes formed by the ligands with uranyl. Density functional theory (DFT) calculations and X-ray absorption fine structure (XAFS) spectroscopy on uranyl-ligand complexes revealed the coordination geometry around the uranyl center at pH 3 and 7.4. High affinity constants (log K ∼17) toward the uranyl ion were determined by displacement titration. A preliminary in vitro chelation study proves that bis-phosphonated pyridine ligands can remove uranium from calmodulin (CaM) at a low dose and in the short term, which supports further uranyl decorporation applications of these ligands.
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Affiliation(s)
- Gaoyang Ye
- IJCLab CNRS-IN2P3, Université Paris-Saclay, 91405 Orsay, France.,Institute of Nuclear and New Energy Technology, Tsinghua University, 100084 Beijing, China
| | - Jérome Roques
- IJCLab CNRS-IN2P3, Université Paris-Saclay, 91405 Orsay, France
| | | | | | | | - Jérémy Brandel
- IPHC, UMR 7178, Université de Strasbourg/CNRS, F-67000 Strasbourg, France
| | | | - Wangsuo Wu
- Radiochemistry Laboratory, Lanzhou University, 730000 Lanzhou, Gansu, China
| | - Éric Simoni
- IJCLab CNRS-IN2P3, Université Paris-Saclay, 91405 Orsay, France
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3
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Affiliation(s)
| | - Gérald Lelong
- Sorbonne Université, Muséum National d’Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et Cosmochimie, IMPMC, 75005 Paris, France
| | - Laurent Cormier
- Sorbonne Université, Muséum National d’Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et Cosmochimie, IMPMC, 75005 Paris, France
| | - Laurence Galoisy
- Sorbonne Université, Muséum National d’Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et Cosmochimie, IMPMC, 75005 Paris, France
| | - Pier-Lorenzo Solari
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin BP 48, 91192 Gif-sur-Yvette, France
| | - Georges Calas
- Sorbonne Université, Muséum National d’Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et Cosmochimie, IMPMC, 75005 Paris, France
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Beccia MR, Matara-Aho M, Reeves B, Roques J, Solari PL, Monfort M, Moulin C, Den Auwer C. New insight into the ternary complexes of uranyl carbonate in seawater. J Environ Radioact 2017; 178-179:343-348. [PMID: 28947086 DOI: 10.1016/j.jenvrad.2017.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/02/2017] [Accepted: 08/12/2017] [Indexed: 06/07/2023]
Abstract
Uranium is naturally present in seawater at trace levels and may in some cases be present at higher concentrations, due to anthropogenic nuclear activities. Understanding uranium speciation in seawater is thus essential for predicting and controlling its behavior in this specific environmental compartment and consequently, its possible impact on living organisms. The carbonato calcic complex Ca2UO2(CO3)3 was previously identified as the main uranium species in natural seawater, together with CaUO2(CO3)32-. In this work, we further investigate the role of the alkaline earth cation in the structure of the ternary uranyl-carbonate complexes. For this purpose, artificial seawater, free of Mg2+ and Ca2+, using Sr2+ as a spectroscopic probe was prepared. Combining TRLIF and EXAFS spectroscopy, together with DFT and theoretical thermodynamic calculations, evidence for the presence of Sr alkaline earth counter ion in the complex structure can be asserted. Furthermore, data suggest that when Ca2+ is replaced by Sr2+, SrUO2(CO3)32- is the main complex in solution and it occurs with the presence of at least one monodentate carbonate in the uranyl coordination sphere.
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Affiliation(s)
- M R Beccia
- Université Côte d'Azur, CNRS, Institut de Chimie de Nice, UMR 7272, 06108 Nice, France.
| | - M Matara-Aho
- Université Côte d'Azur, CNRS, Institut de Chimie de Nice, UMR 7272, 06108 Nice, France; Laboratory of Radiochemistry, Department of Chemistry, University of Helsinki, FI, 00014, Finland
| | - B Reeves
- Université Côte d'Azur, CNRS, Institut de Chimie de Nice, UMR 7272, 06108 Nice, France
| | - J Roques
- Institut de Physique Nucléaire d'Orsay, Université Paris XI Orsay, UMR8608, 91405 Orsay, France
| | - P L Solari
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, F-91192 Gif-sur-Yvette Cedex, France
| | - M Monfort
- CEA, DAM, DIF, F-91297 Arpajon, France
| | - C Moulin
- CEA, DAM, DIF, F-91297 Arpajon, France
| | - C Den Auwer
- Université Côte d'Azur, CNRS, Institut de Chimie de Nice, UMR 7272, 06108 Nice, France.
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5
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Maloubier M, Shuh DK, Minasian SG, Pacold JI, Solari PL, Michel H, Oberhaensli FR, Bottein Y, Monfort M, Moulin C, Den Auwer C. How Do Radionuclides Accumulate in Marine Organisms? A Case Study of Europium with Aplysina cavernicola. Environ Sci Technol 2016; 50:10730-10738. [PMID: 27588898 DOI: 10.1021/acs.est.6b01896] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In the ocean, complex interactions between natural and anthropogenic radionuclides, seawater, and diverse marine biota provide a unique window through which to examine ecosystem and trophic transfer mechanisms in cases of accidental dissemination. The nature of interaction between radionuclides, the marine environment, and marine species is therefore essential for better understanding transfer mechanisms from the hydrosphere to the biosphere. Although data pertaining to the rate of global transfer are often available, little is known regarding the mechanism of environmental transport and uptake of heavy radionuclides by marine species. Among marine species, sponges are immobile active filter feeders and have been identified as hyperaccumulators of several heavy metals. We have selected the Mediterranean sponge Aplysina cavernicola as a model species for this study. Actinide elements are not the only source of radioactive release in cases of civilian nuclear events; however, their physicochemical transfer mechanisms to marine species remain largely unknown. We have targeted europium(III) as a representative of the trivalent actinides such as americium or curium. To unravel biological uptake mechanisms of europium in A. cavernicola, we have combined radiometric (γ) measurements with spectroscopic (time-resolved laser-induced fluorescence spectroscopy, TRLIFS, and X-ray absorption near-edge structure, XANES) and imaging (transmission electron microscopy, TEM, and scanning transmission X-ray microscopy, STXM) techniques. We have observed that the colloids of NaEu(CO3)2·nH2O formed in seawater are taken up by A. cavernicola with no evidence that lethal dose has been reached in our working conditions. Spectroscopic results suggest that there is no change of speciation during uptake. Finally, TEM and STXM images recorded at different locations across a sponge cross section, together with differential cell separation, indicate the presence of europium particles (around 200 nm) mainly located in the skeleton and toward the outer surface of the sponge.
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Affiliation(s)
- Melody Maloubier
- Institut de Chimie de Nice, Université Côte d'Azur and Centre National de la Recherche Scientifique , 06108 Nice, France
- Commissariat à l'Énergie Atomique, Direction des Applications Militaires, DIF , F-91297 Arpajon, France
| | - David K Shuh
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Stefan G Minasian
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Joseph I Pacold
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Pier-Lorenzo Solari
- Synchrotron Soleil , L'Orme des Merisiers, BP 48, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex, France
| | - Hervé Michel
- Institut de Chimie de Nice, Université Côte d'Azur and Centre National de la Recherche Scientifique , 06108 Nice, France
| | - François R Oberhaensli
- Monaco Environment Laboratory, International Atomic Energy Agency , 4 Quai Antoine Ier, 98000, Monaco
| | - Yasmine Bottein
- Monaco Environment Laboratory, International Atomic Energy Agency , 4 Quai Antoine Ier, 98000, Monaco
| | - Marguerite Monfort
- Commissariat à l'Énergie Atomique, Direction des Applications Militaires, DIF , F-91297 Arpajon, France
| | - Christophe Moulin
- Commissariat à l'Énergie Atomique, Direction des Applications Militaires, DIF , F-91297 Arpajon, France
| | - Christophe Den Auwer
- Institut de Chimie de Nice, Université Côte d'Azur and Centre National de la Recherche Scientifique , 06108 Nice, France
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Bès R, Rivenet M, Solari PL, Kvashnina KO, Scheinost AC, Martin PM. Use of HERFD–XANES at the U L3- and M4-Edges To Determine the Uranium Valence State on [Ni(H2O)4]3[U(OH,H2O)(UO2)8O12(OH)3]. Inorg Chem 2016; 55:4260-70. [DOI: 10.1021/acs.inorgchem.6b00014] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- René Bès
- Synchrotron SOLEIL, Ligne de lumière MARS, L’Orme des
Merisiers, Saint Aubin, BP 48, F-91192 Gif-sur-Yvette Cedex, France
- CEA, DEN, DEC, Centre d’études nucléaires de Cadarache, F-13108 Saint Paul
Lez Durance, France
| | - Murielle Rivenet
- Université Lille, CNRS, Centrale Lille, ENSCL, Université Artois, UMR 8181, UCCS, Unité de Catalyse et Chimie du Solide, F-59000 Lille, France
| | - Pier-Lorenzo Solari
- CEA, DEN, DEC, Centre d’études nucléaires de Cadarache, F-13108 Saint Paul
Lez Durance, France
| | - Kristina O. Kvashnina
- Rossendorf Beamline (ROBL) at the European Synchrotron Radiation Facility (ESRF), CS40220, F38043 Grenoble, France
- Helmholtz Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, P.O. Box 510119, 01314 Dresden, Germany
| | - Andreas C. Scheinost
- Rossendorf Beamline (ROBL) at the European Synchrotron Radiation Facility (ESRF), CS40220, F38043 Grenoble, France
- Helmholtz Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, P.O. Box 510119, 01314 Dresden, Germany
| | - Philippe M. Martin
- CEA, DEN, DTEC, Centre d’études nucléaires de Marcoule, Bagnols-sur-Cèze F-30207, France
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7
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Brulfert F, Safi S, Jeanson A, Martinez-Baez E, Roques J, Berthomieu C, Solari PL, Sauge-Merle S, Simoni É. Structural Environment and Stability of the Complexes Formed Between Calmodulin and Actinyl Ions. Inorg Chem 2016; 55:2728-36. [DOI: 10.1021/acs.inorgchem.5b02440] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Florian Brulfert
- Institut de Physique Nucléaire d’Orsay,
CNRS-IN2P3, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay, France
| | - Samir Safi
- Institut de Physique Nucléaire d’Orsay,
CNRS-IN2P3, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay, France
| | - Aurélie Jeanson
- Institut de Physique Nucléaire d’Orsay,
CNRS-IN2P3, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay, France
| | - Ernesto Martinez-Baez
- Institut de Physique Nucléaire d’Orsay,
CNRS-IN2P3, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay, France
| | - Jérôme Roques
- Institut de Physique Nucléaire d’Orsay,
CNRS-IN2P3, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay, France
| | - Catherine Berthomieu
- CEA, IBEB,
Laboratoire des Interactions Protéine Métal, Saint-Paul-lez-Durance, F-13108, France
- CNRS, UMR 7265 Biol Veget & Microbiol Environ, Saint-Paul-lez-Durance, F-13108, France
- Aix Marseille Université, BVME UMR7265, Marseille, F-13284, France
| | | | - Sandrine Sauge-Merle
- CEA, IBEB,
Laboratoire des Interactions Protéine Métal, Saint-Paul-lez-Durance, F-13108, France
- CNRS, UMR 7265 Biol Veget & Microbiol Environ, Saint-Paul-lez-Durance, F-13108, France
- Aix Marseille Université, BVME UMR7265, Marseille, F-13284, France
| | - Éric Simoni
- Institut de Physique Nucléaire d’Orsay,
CNRS-IN2P3, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay, France
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8
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Creff G, Safi S, Roques J, Michel H, Jeanson A, Solari PL, Basset C, Simoni E, Vidaud C, Den Auwer C. Actinide(IV) Deposits on Bone: Potential Role of the Osteopontin-Thorium Complex. Inorg Chem 2015; 55:29-36. [PMID: 26684435 DOI: 10.1021/acs.inorgchem.5b02349] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In case of a nuclear event, contamination (broad or limited) of the population or of specific workers might occur. In such a senario, the fate of actinide contaminants may be of first concern, in particular with regard to human target organs like the skeleton. To improve our understanding of the toxicological processes that might take place, a mechanistic approach is necessary. For instance, ∼50% of Pu(IV) is known from biokinetic data to accumulate in bone, but the underlining mechanisms are almost unknown. In this context, and to obtain a better description of the toxicological mechanisms associated with actinides(IV), we have undertaken the investigation, on a molecular scale, of the interaction of thorium(IV) with osteopontin (OPN) a hyperphosphorylated protein involved in bone turnover. Thorium is taken here as a simple model for actinide(IV) chemistry. In addition, we have selected a phosphorylated hexapeptide (His-pSer-Asp-Glu-pSer-Asp-Glu-Val) that is representative of the peptidic sequence involved in the bone interaction. For both the protein and the biomimetic peptide, we have determined the local environment of Th(IV) within the bioactinidic complex, combining isothermal titration calorimetry, attenuated total reflectance Fourier transform infrared spectroscopy, theoretical calculations with density functional theory, and extended X-ray absorption fine structure spectroscopy at the Th LIII edge. The results demonstrate a predominance of interaction of metal with the phosphate groups and confirmed the previous physiological studies that have highlighted a high affinity of Th(IV) for the bone matrix. Data are further compared with those of the uranyl case, representing the actinyl(V) and actinyl(VI) species. Last, our approach shows the importance of developing simplified systems [Th(IV)-peptide] that can serve as models for more biologically relevant systems.
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Affiliation(s)
- Gaëlle Creff
- Institut de Chimie de Nice, UMR7272, Université Nice Sophia Antipolis , 28 Avenue Valrose, 06108 Nice, France
| | - Samir Safi
- Institut de Physique Nucléaire d'Orsay, UMR8608, Université Paris XI Orsay , 15 Rue Georges Clemenceau, 91405 Orsay, France
| | - Jérôme Roques
- Institut de Physique Nucléaire d'Orsay, UMR8608, Université Paris XI Orsay , 15 Rue Georges Clemenceau, 91405 Orsay, France
| | - Hervé Michel
- Institut de Chimie de Nice, UMR7272, Université Nice Sophia Antipolis , 28 Avenue Valrose, 06108 Nice, France
| | - Aurélie Jeanson
- Institut de Physique Nucléaire d'Orsay, UMR8608, Université Paris XI Orsay , 15 Rue Georges Clemenceau, 91405 Orsay, France
| | - Pier-Lorenzo Solari
- Synchrotron SOLEIL, L'Orme des Merisiers , BP 48, St Aubin, 91192 Gif sur Yvette, France
| | | | - Eric Simoni
- Institut de Physique Nucléaire d'Orsay, UMR8608, Université Paris XI Orsay , 15 Rue Georges Clemenceau, 91405 Orsay, France
| | - Claude Vidaud
- CEA Marcoule, DSV, IBEB, LEPC , 30207 Bagnols sur Cèze, France
| | - Christophe Den Auwer
- Institut de Chimie de Nice, UMR7272, Université Nice Sophia Antipolis , 28 Avenue Valrose, 06108 Nice, France
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Alies B, Solari PL, Hureau C, Faller P. Dynamics of ZnII Binding as a Key Feature in the Formation of Amyloid Fibrils by Aβ11-28. Inorg Chem 2011; 51:701-8. [DOI: 10.1021/ic202247m] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Bruno Alies
- Laboratoire
de Chimie de Coordination
(LCC), CNRS, 205 route de Narbonne, 31077
Toulouse, France
- LCC, Université de Toulouse, UPS, INPT, 31077 Toulouse, France
| | - Pier-Lorenzo Solari
- Synchrotron SOLEIL, L’Orme des merisiers BP48, Saint-Aubin, F-91192 Gif-Sur-Yvette
Cedex, France
| | - Christelle Hureau
- Laboratoire
de Chimie de Coordination
(LCC), CNRS, 205 route de Narbonne, 31077
Toulouse, France
- LCC, Université de Toulouse, UPS, INPT, 31077 Toulouse, France
| | - Peter Faller
- Laboratoire
de Chimie de Coordination
(LCC), CNRS, 205 route de Narbonne, 31077
Toulouse, France
- LCC, Université de Toulouse, UPS, INPT, 31077 Toulouse, France
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10
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Horner O, Mouesca JM, Solari PL, Orio M, Oddou JL, Bonville P, Jouve HM. Spectroscopic description of an unusual protonated ferryl species in the catalase from Proteus mirabilis and density functional theory calculations on related models. Consequences for the ferryl protonation state in catalase, peroxidase and chloroperoxidase. J Biol Inorg Chem 2007; 12:509-25. [PMID: 17237942 DOI: 10.1007/s00775-006-0203-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [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: 05/31/2006] [Accepted: 12/21/2006] [Indexed: 11/24/2022]
Abstract
The catalase from Proteus mirabilis peroxide-resistant bacteria is one of the most efficient heme-containing catalases. It forms a relatively stable compound II. We were able to prepare samples of compound II from P. mirabilis catalase enriched in (57)Fe and to study them by spectroscopic methods. Two different forms of compound II, namely, low-pH compound II (LpH II) and high-pH compound II (HpH II), have been characterized by Mössbauer, extended X-ray absorption fine structure (EXAFS) and UV-vis absorption spectroscopies. The proportions of the two forms are pH-dependent and the pH conversion between HpH II and LpH II is irreversible. Considering (1) the Mössbauer parameters evaluated for four related models by density functional theory methods, (2) the existence of two different Fe-O(ferryl) bond lengths (1.80 and 1.66 A) compatible with our EXAFS data and (3) the pH dependence of the alpha band to beta band intensity ratio in the absorption spectra, we attribute the LpH II compound to a protonated ferryl Fe(IV)-OH complex (Fe-O approximately 1.80 A), whereas the HpH II compound corresponds to the classic ferryl Fe(IV)=O complex (Fe=O approximately 1.66 A). The large quadrupole splitting value of LpH II (measured 2.29 mm s(-1) vs. computed 2.15 mm s(-1)) compared with that of HpH II (measured 1.47 mm s(-1) vs. computed 1.46 mm s(-1)) reflects the protonation of the ferryl group. The relevancy and involvement of such (Fe(IV)=O/Fe(IV)-OH) species in the reactivity of catalase, peroxidase and chloroperoxidase are discussed.
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Affiliation(s)
- O Horner
- Laboratoire de Physicochimie des Métaux en Biologie, UMR CEA/CNRS/Université Joseph Fourier 5155, CEA/Grenoble, 38054, Grenoble Cedex 9, France
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11
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Abstract
In this work, we report state-of-the-art analysis of both Ti K-edge high-resolution XANES and EXAFS data collected on the ETS-10 molecular sieve at the GILDA BM8 beamline of the ESRF facility. The interatomic distances and the angles obtained in our EXAFS study are in fair agreement with the single-crystal XRD data of Wang and Jacobson (Chem. Commun. 1999, 973) and with the recent ab initio periodic study of Damin et al. (J. Phys. Chem. B 2004, 108, 1328) Differently from previous EXAFS work (J. Phys. Chem. 1996, 100, 449), our study supports a model of ETS-10 where the Ti atoms are bonded with two equivalent axial oxygen atoms. This model is also able to reproduce the edge and the post-edge region of the XANES spectrum. Conversely, the weak but well-defined pre-edge peak at 4971.3 eV can be explained only by assuming that a fraction of Ti atoms are in a local geometry similar to that of the pentacoordinated Ti sites in the ETS-4 structure. These Ti atoms in ETS-10 should be the terminal of the -Ti-O-Ti-O-Ti- chains, of which the actual number is strongly increased by the high crystal defectivity (Ti vacancies).
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Affiliation(s)
- C Prestipino
- Department of Inorganic, Physical and Materials Chemistry and NIS Centre of Excellence, Via P. Giuria 7, I-10125 Torino, Italy.
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12
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Borghi E, Solari PL. Structural quantitative information on the active sites of hemocyanins and related model compounds by the XAS approach: the role of multiple-scattering calculations. Micron 2004; 35:81-6. [PMID: 15036299 DOI: 10.1016/j.micron.2003.10.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In this contribution, we will present an overview of the role of the multiple scattering (MS) calculations in the X-ray absorption spectroscopy (XAS) approach in order to extract from experimental data quantitative structural information on the active sites of the hemocyanin derivatives and of the related model compounds considered.
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Affiliation(s)
- E Borghi
- Dipartimento di Chimica, Università La Sapienza, p.le A. Moro 5, 00185 Roma, Italy.
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Cordioli G, Cuoghi L, Solari PL, Berrino F, Crosignani P, Riboli E. [Tumor mortality in a cohort of glass industry workers]. Epidemiol Prev 1987; 9:16-8. [PMID: 2976675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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