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Publications Département B3S


  • M. Amjadi, T. Hallaj, H. Asadollahi, Z. Song, M. de Frutos, et N. Hildebrandt, « Facile synthesis of carbon quantum dot/silver nanocomposite and its application for colorimetric detection of methimazole », Sensors and Actuators B: Chemical, vol. 244, p. 425-432, 2017.

  • H. Azouaoui, C. Montigny, T. Dieudonné, P. Champeil, A. Jacquot, J. L. Vázquez-Ibar, P. Le Maréchal, J. Ulstrup, M. - R. Ash, J. A. Lyons, P. Nissen, et G. Lenoir, « A High and Phosphatidylinositol-4-phosphate (PI4P)-dependent ATPase Activity for the Drs2p/Cdc50p Flippase after Removal of its N- and C-terminal Extensions », Journal of Biological Chemistry, p. jbc.M116.751487, mars 2017.
    Mots-clés : autophosphorylation, B3S, Cdc50 protein, Flippase, inhibition mechanism, limited proteolysis, lipid-protein interaction, LPSM, phosphatidylserine, phosphoinositide.

  • A. Bahloul, E. Pepermans, B. Raynal, N. Wolff, F. Cordier, P. England, S. Nouaille, B. Baron, A. El-Amraoui, J. - P. Hardelin, D. Durand, et C. Petit, « Conformational switch of harmonin, a submembrane scaffold protein of the hair cell mechanoelectrical transduction machinery », FEBS letters, 2017.
    Résumé : Mutations in the gene encoding harmonin, a multi-PDZ domain-containing submembrane protein, cause Usher syndrome type 1 (congenital deafness and balance disorder, as well as early-onset sight loss). The structure of the protein and biological activities of its three different classes of splice isoforms (a, b, and c) remain poorly understood. Combining biochemical and biophysical analyses, we show that harmonin-a1 can switch between open and closed conformations through intramolecular binding of its C-terminal PDZ-binding motif to its N-terminal supramodule NTD-PDZ1 and a flexible PDZ2-PDZ3 linker. This conformational switch presumably extends to most harmonin isoforms, and is expected to have an impact on the interaction with some binding partners, as shown here for cadherin-related 23, another component of the hair cell mechanoelectrical transduction machinery. This article is protected by copyright. All rights reserved.
    Mots-clés : B3S, conformation switch, FAAM, PDZ domain, Usher syndrome.

  • E. Baquero, A. A. Albertini, H. Raux, A. Abou‐Hamdan, E. Boeri‐Erba, M. Ouldali, L. Buonocore, J. K. Rose, J. Lepault, S. Bressanelli, et Y. Gaudin, « Structural intermediates in the fusion‐associated transition of vesiculovirus glycoprotein », The EMBO Journal, vol. 36, nᵒ 5, p. 679-692, mars 2017.
    Mots-clés : B3S, conformational change, glycoprotein, IMAPP, intermediate structures, membrane fusion, RHABDO, Vesiculovirus, VIRO, VIROEM.

  • L. Benkaidali, F. André, G. Moroy, B. Tangour, F. Maurel, et M. Petitjean, « The Cytochrome P450 3A4 Has Three Major Conformations: New Clues to Drug Recognition by this Promiscuous Enzyme », Molecular Informatics, 2017.
    Résumé : We computed the channels of the 3A4 isoform of the cytochrome P450 3A4 (CYP) on the basis of 24 crystal structures extracted from the Protein Data Bank (PDB). We identified three major conformations (denoted C, O1 and O2) using an enhanced version of the CCCPP software that we developed for the present work, while only two conformations (C and O(2) ) are considered in the literature. We established the flowchart of definition of these three conformations in function of the structural and physicochemical parameters of the ligand. The channels are characterized with qualitative and quantitative parameters, and not only with their surrounding secondary structures as it is usually done in the literature.
    Mots-clés : active site access channels, B3S, conformations, CYP 3A4 ligands, cytochromes P450, drug-drug interactions, LSOD.

  • S. E. Cannella, V. Y. Ntsogo Enguéné, M. Davi, C. Malosse, A. C. Sotomayor Pérez, J. Chamot-Rooke, P. Vachette, D. Durand, D. Ladant, et A. Chenal, « Stability, structural and functional properties of a monomeric, calcium–loaded adenylate cyclase toxin, CyaA, from Bordetella pertussis », Scientific Reports, vol. 7, p. 42065, févr. 2017.

  • L. Cao, S. Cantos-Fernandes, et B. Gigant, « The structural switch of nucleotide-free kinesin », Scientific Reports, vol. 7, p. 42558, févr. 2017.

  • P. Cardol et A. Krieger-Liszkay, « From light capture to metabolic needs, oxygenic photosynthesis is an ever-expanding field of study in plants, algae and cyanobacteria », Physiologia Plantarum, 2017.
    Résumé : Understanding of the molecular mechanisms of photosynthetic electron and proton transports and their regulation in plants and algae in response to changes in environmental conditions is an important issue for fundamental research on photosynthesis, and may extend even to practical applications by identifying important sites for improvement of photosynthesis. The significance and often centrality of regulatory mechanisms of photosynthetic electron transport is well established for processes in plant acclimation. In recent years, significant advancements have been achieved in understanding of regulatory processes such as dissipation of excess energy in the antenna systems, state transitions, cyclic electron flow, oxygen reduction by flavodiiron enzymes and many others.
    Mots-clés : B3S, MROP.

  • M. - F. Carlier et S. Shekhar, « Global treadmilling coordinates actin turnover and controls the size of actin networks », Nature Reviews Molecular Cell Biology, mars 2017.

  • V. Chaptal, F. Delolme, A. Kilburg, S. Magnard, C. Montigny, M. Picard, C. Prier, L. Monticelli, O. Bornert, M. Agez, S. Ravaud, C. Orelle, R. Wagner, A. Jawhari, I. Broutin, E. Pebay-Peyroula, J. - M. Jault, H. R. Kaback, M. le Maire, et P. Falson, « Quantification of Detergents Complexed with Membrane Proteins », Scientific Reports, vol. 7, p. 41751, févr. 2017.

  • J. - P. Charbonnier, E. M. van Rikxoort, A. A. A. Setio, C. M. Schaefer-Prokop, B. van Ginneken, et F. Ciompi, « Improving airway segmentation in computed tomography using leak detection with convolutional networks », Medical Image Analysis, vol. 36, p. 52-60, 2017.

  • M. Clémancey, T. Cantat, G. Blondin, J. - M. Latour, P. Dorlet, et G. Lefèvre, « Structural Insights into the Nature of Fe(0) and Fe(I) Low-Valent Species Obtained upon the Reduction of Iron Salts by Aryl Grignard Reagents », Inorganic Chemistry, vol. 56, nᵒ 7, p. 3834-3848, 2017.
    Résumé : Mechanistic studies of the reduction of Fe(III) and Fe(II) salts by aryl Grignard reagents in toluene/tetrahydrofuran mixtures in the absence of a supporting ligand, as well as structural insights regarding the nature of the low-valent iron species obtained at the end of this reduction process, are reported. It is shown that several reduction pathways can be followed, depending on the starting iron precursor. We demonstrate, moreover, that these pathways lead to a mixture of Fe(0) and Fe(I) complexes regardless of the nature of the precursor. Mössbauer and (1)H NMR spectroscopies suggest that diamagnetic 16-electron bisarene complexes such as (η(4)-C6H5Me)2Fe(0) can be formed as major species (85% of the overall iron quantity). The formation of a η(6)-arene-ligated low-spin Fe(I) complex as a minor species (accounting for ca. 15% of the overall iron quantity) is attested by Mössbauer spectroscopy, as well as by continuous-wave electron paramagnetic resonance (EPR) and pulsed-EPR (HYSCORE) spectroscopies. The nature of the Fe(I) coordination sphere is discussed by means of isotopic labeling experiments and density functional theory calculations. It is shown that the most likely low-spin Fe(I) candidate obtained in these systems is a diphenylarene-stabilized species [(η(6)-C6H5Me)Fe(I)Ph2](-) exhibiting an idealized C2v topology. This enlightens the nature of the lowest valence states accommodated by iron during the reduction of Fe(III) and Fe(II) salts by aryl Grignard reagents in the absence of any additional coligand, which so far remained rather unknown. The reactivity of these low-valent Fe(I) and Fe(0) complexes in aryl-heteroaryl Kumada cross-coupling conditions has also been investigated, and it is shown that the zerovalent Fe(0) species can be used efficiently as a precursor in this reaction, whereas the Fe(I) oxidation state does not exhibit any reactivity.
    Mots-clés : B3S, LSOD.

  • P. Cuniasse, P. Tavares, E. V. Orlova, et S. Zinn-Justin, « Structures of biomolecular complexes by combination of NMR and cryoEM methods », Current Opinion in Structural Biology, vol. 43, p. 104-113, 2017.

  • L. Dhers, N. Pietrancosta, L. Ducassou, B. Ramassamy, J. Dairou, M. Jaouen, F. André, D. Mansuy, et J. - L. Boucher, « Spectral and 3D model studies of the interaction of orphan human cytochrome P450 2U1 with substrates and ligands », Biochimica et Biophysica Acta (BBA) - General Subjects, vol. 1861, nᵒ 1, p. 3144-3153, 2017.

  • T. Di Meo, W. Ghattas, C. Herrero, C. Velours, P. Minard, J. - P. Mahy, R. Ricoux, et A. Urvoas, « αRep A3: A versatile artificial scaffold for metalloenzyme design », Chemistry (Weinheim an Der Bergstrasse, Germany), 2017.
    Résumé : αRep is a new family of artificial proteins based on a thermostable alpha-helical repeated motif. One of its members, αRep A3, forms a stable homo-dimer with a wide cleft that is able to receive metal complexes and thus appears as suitable for generating new artificial biocatalysts. Based on the crystal structure of αRep A3, two positions (F119 and Y26) were chosen and changed independently into cysteine residues. A phenanthroline ligand was covalently attached to the unique cysteine of each protein variant and the corresponding biohybrids were purified and characterized. Once mutated and coupled to phenanthroline, the protein remained folded and dimeric. Copper(II) was bound specifically by the two biohybrids with two different binding modes and, in addition, the holo biohybrid A3F119NPH was found to be able to catalyze enantioselectively the Diels-Alder (D-A) cycloaddition with up to 62% ee. This study validates the choice of the αRep A3 dimer as a protein scaffold and provides a new promising route for the design and production of new enantioselective biohybrids based on entirely artificial proteins issued from a highly diverse library.
    Mots-clés : artificial repeat proteins, B3S, Diels-Alder reaction, Enantioselective Catalysis, MIP, PF, PIM.

  • S. A. Díaz, G. Lasarte Aragonés, S. Buckhout-White, X. Qiu, E. Oh, K. Susumu, J. S. Melinger, A. L. Huston, N. Hildebrandt, et I. L. Medintz, « Bridging Lanthanide to Quantum Dot Energy Transfer with a Short-Lifetime Organic Dye », The Journal of Physical Chemistry Letters, p. 2182-2188, 2017.
    Résumé : Semiconductor nanocrystals or quantum dots (QDs) should act as excellent Förster resonance energy transfer (FRET) acceptors due to their large absorption cross section, tunable emission, and high quantum yields. Engaging this type of FRET can be complicated due to direct excitation of the QD acceptor along with its longer excited-state lifetime. Many cases of QDs acting as energy transfer acceptors are within time-gated FRET from long-lifetime lanthanides, which allow the QDs to decay before observing FRET. Efficient QD sensitization requires the lanthanide to be in close proximity to the QD. To overcome the lifetime mismatch issues and limited transfer range, we utilized a Cy3 dye to bridge the energy transfer from an extremely long lived terbium emitter to the QD. We demonstrated that short-lifetime dyes can be used as energy transfer relays between extended lifetime components and in this way increased the distance of terbium-QD FRET to ∼14 nm.
    Mots-clés : B3S, NANO.

  • G. Dimchev, A. Steffen, F. Kage, V. Dimchev, J. Pernier, M. - F. Carlier, et K. Rottner, « Efficiency of lamellipodia protrusion is determined by the extent of cytosolic actin assembly », Molecular Biology of the Cell, p. mbc.E16-05-0334, mars 2017.

  • Y. Duroc, R. Kumar, L. Ranjha, C. Adam, R. Guérois, K. Md Muntaz, M. - C. Marsolier-Kergoat, F. Dingli, R. Laureau, D. Loew, B. Llorente, J. - B. Charbonnier, P. Cejka, et V. Borde, « Concerted action of the MutLβ heterodimer and Mer3 helicase regulates the global extent of meiotic gene conversion », eLife, vol. 6, janv. 2017.
    Mots-clés : AMIG, B3S, biochemistry, Chromosomes, genes, INTGEN, Meiosis, mismatch repair, Recombination, S. cerevisiae.

  • N. El Bakkali-Tahéri, S. Tachon, M. Orio, S. Bertaina, M. Martinho, V. Robert, M. Réglier, T. Tron, P. Dorlet, et A. J. Simaan, « Characterization of Cu(II)-reconstituted ACC Oxidase using experimental and theoretical approaches », Archives of Biochemistry and Biophysics, 2017.
    Résumé : 1-Aminocyclopropane-1-carboxylic acid oxidase (ACCO) is a non heme iron(II) containing enzyme that catalyzes the final step of the ethylene biosynthesis in plants. The iron(II) ion is bound in a facial triad composed of two histidines and one aspartate (H177, D179 and H234). Several active site variants were generated to provide alternate binding motifs and the enzymes were reconstituted with copper(II). Continuous wave (cw) and pulsed Electron Paramagnetic Resonance (EPR) spectroscopies as well as Density Functional Theory (DFT) calculations were performed and models for the copper(II) binding sites were deduced. In all investigated enzymes, the copper ion is equatorially coordinated by the two histidine residues (H177 and H234) and probably two water molecules. The copper-containing enzymes are inactive, even when hydrogen peroxide is used in peroxide shunt approach. EPR experiments and DFT calculations were undertaken to investigate substrate's (ACC) binding on the copper ion and the results were used to rationalize the lack of copper-mediated activity.
    Mots-clés : ACC Oxidase, B3S, Copper, Density functional theory calculations, Electron paramagnetic resonance, Ethylene, LSOD.

  • E. Errasti-Murugarren, A. Rodríguez-Banqueri, et J. L. Vázquez-Ibar, « Split GFP Complementation as Reporter of Membrane Protein Expression and Stability in E. coli: A Tool to Engineer Stability in a LAT Transporter », Methods in Molecular Biology (Clifton, N.J.), vol. 1586, p. 181-195, 2017.
    Résumé : Obtaining enough quantity of recombinant membrane transport proteins with optimal purity and stability for structural studies is a remarkable challenge. In this chapter, we describe a protocol to engineer SteT, the amino acid transporter of Bacillus subtilis, in order to improve its heterologous expression in Escherichia coli and its stability in detergent micelles. We built a library of 70 SteT mutants, combining a random mutagenesis protocol with a split GFP assay as reporter of protein folding and membrane insertion. Mutagenesis was restricted to residues situated in the transmembrane domains. Improved versions of SteT were successfully identified after analyzing the expression yield and monodispersity in detergent micelles of the library's members.
    Mots-clés : B3S, FSEC, Heterologous expression, LAT, LPSM, Membrane Transport Proteins, Split GFP, SteT.

  • S. Fieulaine, R. Alves de Sousa, L. Maigre, K. Hamiche, M. Alimi, J. - M. Bolla, A. Taleb, A. Denis, J. - M. Pagès, I. Artaud, T. Meinnel, et C. Giglione, « Corrigendum: A unique peptide deformylase platform to rationally design and challenge novel active compounds », Scientific Reports, vol. 7, p. 39365, janv. 2017.

  • V. R. Figliuolo, L. E. B. Savio, H. Safya, H. Nanini, C. Bernardazzi, A. Abalo, H. S. P. de Souza, J. Kanellopoulos, P. Bobé, C. M. L. M. Coutinho, et R. Coutinho-Silva, « P2X7 receptor promotes intestinal inflammation in chemically induced colitis and triggers death of mucosal regulatory T cells », Biochimica Et Biophysica Acta, 2017.
    Résumé : P2X7 receptor activation contributes to inflammation development in different pathologies. We previously reported that the P2X7 receptor is over-expressed in the gut mucosa of patients with inflammatory bowel disease, and that P2X7 inhibition protects against chemically induced colitis. Here, we investigated in detail the role of the P2X7 receptor in inflammatory bowel disease development, by treating P2X7 knockout (KO) and WT mice with two different (and established) colitis inductors. P2X7 KO mice were protected against gut inflammation induced by 2,4,6-trinitrobenzenesulfonic acid or oxazolone, with no weight loss or gut histological alterations after treatment. P2X7 receptor knockout induced regulatory T cell accumulation in the colon, as evaluated by qRT-PCR for FoxP3 expression and immunostaining for CD90/CD45RB(low). Flow cytometry analysis of mesenteric lymph node cells showed that P2X7 activation (by ATP) triggered regulatory T cell death. In addition, such cells from P2X7 KO mice expressed more CD103, suggesting increased migration of regulatory T cells to the colon (relative to the WT). Our results show that the P2X7 has a key role during inflammation development in inflammatory bowel disease, by triggering the death and retention in the mesenteric lymph nodes of regulatory T cells that would otherwise promote immune system tolerance in the gut.
    Mots-clés : ATP, B3S, colitis, MIP, P2X7 receptor, regulatory T cells.

  • N. Hildebrandt, C. M. Spillmann, W. R. Algar, T. Pons, M. H. Stewart, E. Oh, K. Susumu, S. A. Díaz, J. B. Delehanty, et I. L. Medintz, « Energy Transfer with Semiconductor Quantum Dot Bioconjugates: A Versatile Platform for Biosensing, Energy Harvesting, and Other Developing Applications », Chemical Reviews, vol. 117, nᵒ 2, p. 536-711, janv. 2017.

  • J. Ho, E. Kish, D. D. Méndez-Hernández, K. WongCarter, S. Pillai, G. Kodis, J. Niklas, O. G. Poluektov, D. Gust, T. A. Moore, A. L. Moore, V. S. Batista, et B. Robert, « Triplet-triplet energy transfer in artificial and natural photosynthetic antennas », Proceedings of the National Academy of Sciences of the United States of America, 2017.
    Résumé : In photosynthetic organisms, protection against photooxidative stress due to singlet oxygen is provided by carotenoid molecules, which quench chlorophyll triplet species before they can sensitize singlet oxygen formation. In anoxygenic photosynthetic organisms, in which exposure to oxygen is low, chlorophyll-to-carotenoid triplet-triplet energy transfer (T-TET) is slow, in the tens of nanoseconds range, whereas it is ultrafast in the oxygen-rich chloroplasts of oxygen-evolving photosynthetic organisms. To better understand the structural features and resulting electronic coupling that leads to T-TET dynamics adapted to ambient oxygen activity, we have carried out experimental and theoretical studies of two isomeric carotenoporphyrin molecular dyads having different conformations and therefore different interchromophore electronic interactions. This pair of dyads reproduces the characteristics of fast and slow T-TET, including a resonance Raman-based spectroscopic marker of strong electronic coupling and fast T-TET that has been observed in photosynthesis. As identified by density functional theory (DFT) calculations, the spectroscopic marker associated with fast T-TET is due primarily to a geometrical perturbation of the carotenoid backbone in the triplet state induced by the interchromophore interaction. This is also the case for the natural systems, as demonstrated by the hybrid quantum mechanics/molecular mechanics (QM/MM) simulations of light-harvesting proteins from oxygenic (LHCII) and anoxygenic organisms (LH2). Both DFT and electron paramagnetic resonance (EPR) analyses further indicate that, upon T-TET, the triplet wave function is localized on the carotenoid in both dyads.
    Mots-clés : artificial photosynthesis, B3S, DFT calculations, LBMS, Photoprotection, Resonance Raman, triplet–triplet energy transfer.

  • F. Kage, M. Winterhoff, V. Dimchev, J. Mueller, T. Thalheim, A. Freise, S. Brühmann, J. Kollasser, J. Block, G. Dimchev, M. Geyer, H. - J. Schnittler, C. Brakebusch, T. E. B. Stradal, M. - F. Carlier, M. Sixt, J. Käs, J. Faix, et K. Rottner, « FMNL formins boost lamellipodial force generation », Nature Communications, vol. 8, p. 14832, mars 2017.

  • E. Karakas, C. Taveneau, S. Bressanelli, M. Marchi, B. Robert, et S. Abel, « Derivation of original RESP atomic partial charges for MD simulations of the LDAO surfactant with AMBER: applications to a model of micelle and a fragment of the lipid kinase PI4KA », Journal of Biomolecular Structure and Dynamics, vol. 35, nᵒ 1, p. 159-181, janv. 2017.
    Mots-clés : Amber, B3S, Dimethylamines, fluorescence spectroscopy, IMAPP, LBMS, LDAO surfactant, lipid kinase PI4KA, Lipids, MD simulation, micelle, Micelles, Minor Histocompatibility Antigens, Molecular Conformation, Molecular Dynamics Simulation, molecular modeling, Phosphotransferases (Alcohol Group Acceptor), Protein Binding, Proteins, Static Electricity, Surface-Active Agents.

  • P. V. Krasteva et H. Sondermann, « Versatile modes of cellular regulation via cyclic dinucleotides », Nature Chemical Biology, vol. 13, nᵒ 4, p. 350-359, mars 2017.

  • J. Lang, A. Vigouroux, A. El Sahili, A. Kwasiborski, M. Aumont-Nicaise, Y. Dessaux, J. A. Shykoff, S. Moréra, et D. Faure, « Fitness costs restrict niche expansion by generalist niche-constructing pathogens », The ISME Journal, vol. 11, nᵒ 2, p. 374-385, 2017.
    Mots-clés : B3S, MESB3S, MICROBIO, PBI, PF, PIM.

  • A. Le Dur, T. L. Laï, M. - G. Stinnakre, A. Laisné, N. Chenais, S. Rakotobe, B. Passet, F. Reine, S. Soulier, L. Herzog, G. Tilly, H. Rézaei, V. Béringue, J. - L. Vilotte, et H. Laude, « Divergent prion strain evolution driven by PrP(C) expression level in transgenic mice », Nature Communications, vol. 8, p. 14170, 2017.
    Résumé : Prions induce a fatal neurodegenerative disease in infected host brain based on the refolding and aggregation of the host-encoded prion protein PrP(C) into PrP(Sc). Structurally distinct PrP(Sc) conformers can give rise to multiple prion strains. Constrained interactions between PrP(C) and different PrP(Sc) strains can in turn lead to certain PrP(Sc) (sub)populations being selected for cross-species transmission, or even produce mutation-like events. By contrast, prion strains are generally conserved when transmitted within the same species, or to transgenic mice expressing homologous PrP(C). Here, we compare the strain properties of a representative sheep scrapie isolate transmitted to a panel of transgenic mouse lines expressing varying levels of homologous PrP(C). While breeding true in mice expressing PrP(C) at near physiological levels, scrapie prions evolve consistently towards different strain components in mice beyond a certain threshold of PrP(C) overexpression. Our results support the view that PrP(C) gene dosage can influence prion evolution on homotypic transmission.
    Mots-clés : ACTIN, B3S.

  • M. J. Llansola-Portoles, R. Litvin, C. Ilioaia, A. A. Pascal, D. Bina, et B. Robert, « Pigment structure in the violaxanthin-chlorophyll-a-binding protein VCP », Photosynthesis Research, 2017.
    Résumé : Resonance Raman spectroscopy was used to evaluate pigment-binding site properties in the violaxanthin-chlorophyll-a-binding protein (VCP) from Nannochloropsis oceanica. The pigments bound to this antenna protein are chlorophyll-a, violaxanthin, and vaucheriaxanthin. The molecular structures of bound Chl-a molecules are discussed with respect to those of the plant antenna proteins LHCII and CP29, the crystal structures of which are known. We show that three populations of carotenoid molecules are bound by VCP, each of which is in an all-trans configuration. We assign the lower-energy absorption transition of each of these as follows. One violaxanthin population absorbs at 485 nm, while the second population is red-shifted and absorbs at 503 nm. The vaucheriaxanthin population absorbs at 525 nm, a position red-shifted by 2138 cm(-1) as compared to isolated vaucheriaxanthin in n-hexane. The red-shifted violaxanthin is slightly less planar than the blue-absorbing one, as observed for the two central luteins in LHCII, and we suggest that these violaxanthins occupy the two equivalent binding sites in VCP at the centre of the cross-brace. The presence of a highly red-shifted vaucheriaxanthin in VCP is reminiscent of the situation of FCP, in which (even more) highly red-shifted populations of fucoxanthin are present. Tuning carotenoids to absorb in the green-yellow region of the visible spectrum appears to be a common evolutionary response to competition with other photosynthetic species in the aquatic environment.
    Mots-clés : B3S, Carotenoids, LBMS, Light-harvesting complex, Nannochloropsis oceanica, Resonance Raman, VCP.

  • M. J. Llansola-Portoles, R. Sobotka, E. Kish, M. K. Shukla, A. A. Pascal, T. Polívka, et B. Robert, « Twisting a β-Carotene, an Adaptive Trick from Nature for Dissipating Energy during Photoprotection », Journal of Biological Chemistry, vol. 292, nᵒ 4, p. 1396-1403, janv. 2017.
    Mots-clés : B3S, carotenoid, Chlorophyll, Cyanobacteria, LBMS, light-harvesting complex (antenna complex), photosynthesis.

  • F. Ma, L. - J. Yu, M. J. Llansola-Portoles, B. Robert, Z. - Y. Wang-Otomo, et R. van Grondelle, « Metal Cations Induced αβ-BChl a Heterogeneity in LH1 as Revealed by Temperature-Dependent Fluorescence Splitting », Chemphyschem: A European Journal of Chemical Physics and Physical Chemistry, 2017.
    Résumé : Two spectral forms of the core light-harvesting complex (LH1) of the purple bacterium Thermochromatium (Tch.) tepidum, the native Ca(2+) -binding and the Ba(2+) -substituted one, exhibit different fluorescence (FL) emission spectra at low temperature (T). While Ca-LH1 exhibits one emission band, an unusual splitting of the fluorescence is observed for Ba-LH1. These two sub-bands display the same spectral-width dependence according to T, but their intensity evolves differently with T. Based on the crystal structures, we propose that the FL splitting originates from a large αβ-BChl a transition energy heterogeneity, ≈600 cm(-1) , which is much larger compared with other LH1 and LH2 complexes (80-200 cm(-1) ). This large heterogeneity is induced by the inhomogeneous Coulomb (and possibly hydrogen-bonding) interactions exerted by Ba(2+) . The energy levels of the two LH1s were compared using exciton calculations in combination with Redfield theory. To simulate the FL splitting, an electronic transition containing two resonant bands was considered. This work shows how metal cations incorporated into the polypeptide modulate the electronic properties of BChl a aggregates.
    Mots-clés : B3S, core light-harvesting complex, fluorescence spectroscopy, LBMS, Redfield theory, transition energy, αβ-BChl a heterogeneity.

  • M. Ma, I. Li de la Sierra-Gallay, N. Lazar, O. Pellegrini, D. Durand, A. Marchfelder, C. Condon, et H. van Tilbeurgh, « The crystal structure of Trz1, the long form RNase Z from yeast », Nucleic Acids Research, avr. 2017.

  • P. K. Mandal, D. Shukla, V. Govind, Y. Boulard, et L. Ersland, « Glutathione Conformations and Its Implications for in vivo Magnetic Resonance Spectroscopy », Journal of Alzheimer's disease: JAD, 2017.
    Résumé : Glutathione (GSH) is a major antioxidant in humans that is involved in the detoxification of reactive radicals and peroxides. The molecular structural conformations of GSH depend on the surrounding micro-environment, and it has been experimentally evaluated using NMR and Raman spectroscopic techniques as well as by molecular dynamics simulation studies. The converging report indicates that GSH exists mainly in two major conformations, i.e., "extended" and "folded". The NMR-derived information on the GSH conformers is essential to obtain optimal acquisition parameters in in vivo MRS experiments targeted for GSH detection. To further investigate the implications of GSH conformers in in vivo MRS studies and their relative proportions in healthy and pathological conditions, a multi-center clinical research study is necessary with a common protocol for GSH detection and quantification.
    Mots-clés : Antioxidant, B3S, Brain, conformation, Glutathione, IMAPP, Magnetic Resonance Spectroscopy, molecular dynamics, nuclear magnetic resonance.

  • W. Mao, P. Daligaux, N. Lazar, T. Ha-Duong, C. Cavé, H. van Tilbeurgh, P. M. Loiseau, et S. Pomel, « Biochemical analysis of leishmanial and human GDP-Mannose Pyrophosphorylases and selection of inhibitors as new leads », Scientific Reports, vol. 7, nᵒ 1, 2017.

  • A. Mezzetti et W. Leibl, « Time-resolved infrared spectroscopy in the study of photosynthetic systems », Photosynthesis Research, vol. 131, nᵒ 2, p. 121-144, 2017.
    Résumé : Time-resolved (TR) infrared (IR) spectroscopy in the nanosecond to second timescale has been extensively used, in the last 30 years, in the study of photosynthetic systems. Interesting results have also been obtained at lower time resolution (minutes or even hours). In this review, we first describe the used techniques-dispersive IR, laser diode IR, rapid-scan Fourier transform (FT)IR, step-scan FTIR-underlying the advantages and disadvantages of each of them. Then, the main TR-IR results obtained so far in the investigation of photosynthetic reactions (in reaction centers, in light-harvesting systems, but also in entire membranes or even in living organisms) are presented. Finally, after the general conclusions, the perspectives in the field of TR-IR applied to photosynthesis are described.
    Mots-clés : B3S, Bacterial reaction centers, Carotenoids, Chlorophyll, Electron transfer, FTIR difference spectroscopy, Infrared, Kinetics, Light-harvesting systems, LPB, photosynthesis, Photosynthetic Reaction Center Complex Proteins, Photosystem I, Photosystem II, Proton transfer, Rapid-scan FTIR, Reaction centers, Rhodobacter sphaeroides, Spectroscopy, Fourier Transform Infrared, Step-scan FTIR, Thylakoids, Ubiquinone, Vibrational spectroscopy.

  • C. Mignée, R. Mutoh, A. Krieger-Liszkay, G. Kurisu, et P. Sétif, « Gallium ferredoxin as a tool to study the effects of ferredoxin binding to photosystem I without ferredoxin reduction », Photosynthesis Research, févr. 2017.

  • C. Montigny, T. Dieudonné, S. Orlowski, J. L. Vázquez-Ibar, C. Gauron, D. Georgin, S. Lund, M. le Maire, J. V. Møller, P. Champeil, et G. Lenoir, « Slow Phospholipid Exchange between a Detergent-Solubilized Membrane Protein and Lipid-Detergent Mixed Micelles: Brominated Phospholipids as Tools to Follow Its Kinetics », PLOS ONE, vol. 12, nᵒ 1, p. e0170481, janv. 2017.

  • D. Moonshiram, A. Picón, A. Vazquez-Mayagoitia, X. Zhang, M. - F. Tu, P. Garrido-Barros, J. - P. Mahy, F. Avenier, et A. Aukauloo, « Elucidating light-induced charge accumulation in an artificial analogue of methane monooxygenase enzymes using time-resolved X-ray absorption spectroscopy », Chemical Communications (Cambridge, England), vol. 53, nᵒ 18, p. 2725-2728, 2017.
    Résumé : We report the use of time-resolved X-ray absorption spectroscopy in the ns-μs time scale to track the light induced two electron transfer processes in a multi-component photocatalytic system, consisting of [Ru(bpy)3](2+)/ a diiron(iii,iii) model/triethylamine. EXAFS analysis with DFT calculations confirms the structural configurations of the diiron(iii,iii) and reduced diiron(ii,ii) states.
    Mots-clés : B3S, LPB.

  • T. Motomura, M. Suga, R. Hienerwadel, A. Nakagawa, T. - L. Lai, W. Nitschke, T. Kuma, M. Sugiura, A. Boussac, et J. - R. Shen, « Crystal structure and redox properties of a novel cyanobacterial heme-protein with a His/Cys heme axial ligation and a per-arnt-sim (PAS)-like domain », The Journal of Biological Chemistry, 2017.
    Résumé : Photosystem II (PSII) catalyzes the light-induced water oxidation leading to the generation of dioxygen indispensable for sustaining aerobic life on Earth. The PSII reaction center is composed of D1 and D2 proteins encoded by the psbA and psbD genes, respectively. In cyanobacteria, different psbA genes are present in the genome. The thermophilic cyanobacterium Thermosynechococcus elongatus contains 3 psbA genes, psbA1, psbA2 and psbA3 and a new c-type heme protein, Tll0287, was found to be expressed in a strain expressing the psbA2 gene only, but the structure and function of Tll0287 are unknown. Here we solved the crystal structure of Tll0287 at a 2.0 Å resolution. The overall structure of Tll0287 was found to be similar to some kinases and sensor proteins with a per-arnt-sim (PAS)-like domain, rather than to other c-type cytochromes. The 5(th) and 6(th) axial ligands for the heme were Cys and His, instead of the His/Met or His/His ligand pairs observed for most of the c-type hemes. The redox potential, E1/2, of Tll0287 was -255 ± 20 mV versus normal hydrogen electrode at pH values above 7.5. Below this pH value, the E1/2 increased by ≈57 mV/pH unit at 15°C, suggesting the involvement of a protonatable group with a pKred = 7.2 ± 0.3. Possible functions of Tll0287 as a redox sensor under micro-aerobic conditions or a cytochrome subunit of an H2S-oxidising system, are discussed in view of the environmental conditions in which psbA2 is expressed as well as phylogenetic analysis, structural and sequence homologies.
    Mots-clés : ACTIN, B3S, cytochrome, D1 protein, Heme, His-Cys heme axial coordination, PAS domain, PAS-like domain, photosynthesis, Photosystem II, PS2, Tll0287, x-ray crystallography.

  • C. Pattamadilok, V. Chanoine, C. Pallier, J. - L. Anton, B. Nazarian, P. Belin, et J. C. Ziegler, « Automaticity of phonological and semantic processing during visual word recognition », NeuroImage, vol. 149, p. 244-255, 2017.
    Résumé : Reading involves activation of phonological and semantic knowledge. Yet, the automaticity of the activation of these representations remains subject to debate. The present study addressed this issue by examining how different brain areas involved in language processing responded to a manipulation of bottom-up (level of visibility) and top-down information (task demands) applied to written words. The analyses showed that the same brain areas were activated in response to written words whether the task was symbol detection, rime detection, or semantic judgment. This network included posterior, temporal and prefrontal regions, which clearly suggests the involvement of orthographic, semantic and phonological/articulatory processing in all tasks. However, we also found interactions between task and stimulus visibility, which reflected the fact that the strength of the neural responses to written words in several high-level language areas varied across tasks. Together, our findings suggest that the involvement of phonological and semantic processing in reading is supported by two complementary mechanisms. First, an automatic mechanism that results from a task-independent spread of activation throughout a network in which orthography is linked to phonology and semantics. Second, a mechanism that further fine-tunes the sensitivity of high-level language areas to the sensory input in a task-dependent manner.
    Mots-clés : Automatic activation, B3S, Bottom-up process, INTGEN, Stimulus-driven, Task-dependent, Top-down process.

  • P. Pétriacq, L. de Bont, L. Genestout, J. Hao, C. Laureau, I. Florez-Sarasa, T. Rzigui, G. Queval, F. Gilard, C. Mauve, F. Guérard, M. Lamothe-Sibold, J. Marion, C. Fresneau, S. Brown, A. Danon, A. Krieger-Liszkay, R. Berthomé, M. Ribas-Carbo, G. Tcherkez, G. Cornic, B. Pineau, B. Gakière, et R. De Paepe, « Photoperiod Affects the Phenotype of Mitochondrial Complex I Mutants », Plant Physiology, vol. 173, nᵒ 1, p. 434-455, 2017.
    Mots-clés : B3S, BIOCELL, DYNBSJ, MROP, PF, PHOT.

  • E. Peuchant, M. - L. Bats, I. Moranvillier, M. Lepoivre, J. Guitton, D. Wendum, M. - L. Lacombe, F. Moreau-Gaudry, M. Boissan, et S. Dabernat, « Metastasis suppressor NM23 limits oxidative stress in mammals by preventing activation of stress-activated protein kinases/JNKs through its nucleoside diphosphate kinase activity », FASEB journal: official publication of the Federation of American Societies for Experimental Biology, vol. 31, nᵒ 4, p. 1531-1546, 2017.
    Résumé : NME1 (nonmetastatic expressed 1) gene, which encodes nucleoside diphosphate kinase (NDPK) A [also known as nonmetastatic clone 23 (NM23)-H1 in humans and NM23-M1 in mice], is a suppressor of metastasis, but several lines of evidence-mostly from plants-also implicate it in the regulation of the oxidative stress response. Here, our aim was to investigate the physiologic relevance of NDPK A with respect to the oxidative stress response in mammals and to study its molecular basis. NME1-knockout mice died sooner, suffered greater hepatocyte injury, and had lower superoxide dismutase activity than did wild-type (WT) mice in response to paraquat-induced acute oxidative stress. Deletion of NME1 reduced total NDPK activity and exacerbated activation of the stress-related MAPK, JNK, in the liver in response to paraquat. In a mouse transformed hepatocyte cell line and in primary cultures of normal human keratinocytes, MAPK activation in response to H2O2 and UVB, respectively, was dampened by expression of NM23-M1/NM23-H1, dependent on its NDPK catalytic activity. Furthermore, excess or depletion of NM23-M1/NM23-H1 NDPK activity did not affect the intracellular bulk concentration of nucleoside di- and triphosphates. NME1-deficient mouse embryo fibroblasts grew poorly in culture, were more sensitive to stress than WT fibroblasts, and did not immortalize, which suggested that they senesce earlier than do WT fibroblasts. Collectively, these results indicate that the NDPK activity of NM23-M1/NM23-H1 protects cells from acute oxidative stress by inhibiting activation of JNK in mammal models.-Peuchant, E., Bats, M.-L., Moranvillier, I., Lepoivre, M., Guitton, J., Wendum, D., Lacombe, M.-L., Moreau-Gaudry, F., Boissan, M., Dabernat, S. Metastasis suppressor NM23 limits oxidative stress in mammals by preventing activation of stress-activated protein kinases/JNKs through its nucleoside diphosphate kinase activity.
    Mots-clés : B3S, hepatocyte, keratinocyte, LBMS, MAPK, NDPK.

  • X. Qiu, J. Guo, Z. Jin, I. L. Medintz, et N. Hildebrandt, « Multiplexed Nucleic Acid Hybridization Assays Using Single-FRET-Pair Distance-Tuning », Small, p. 1700332, 2017.

  • H. Renault, M. De Marothy, G. Jonasson, P. Lara, D. R. Nelson, I. M. Nilsson, F. André, G. von Heijne, et D. Werck-Reichhart, « Gene duplication leads to altered membrane topology of a cytochrome P450 enzyme in seed plants », Molecular Biology and Evolution, 2017.
    Résumé : Evolution of the phenolic metabolism was critical for the transition of plants from water to land. A cytochrome P450, CYP73, with cinnamate 4-hydroxylase (C4H) activity, catalyzes the first plant-specific and rate-limiting step in this pathway. The CYP73 gene is absent from green algae, and first detected in bryophytes. A CYP73 duplication occurred in the ancestor of seed plants and was retained in Taxaceae and most angiosperms. In spite of a clear divergence in primary sequence, both paralogs can fulfill comparable cinnamate hydroxylase roles both in vitro and in vivo. One of them seems dedicated to the biosynthesis of lignin precursors. Its N-terminus forms a single membrane spanning helix and its properties and length are highly constrained. The second is characterized by an elongated and variable N-terminus, reminiscent of ancestral CYP73s. Using as proxies the Brachypodium distachyon proteins, we show that the elongation of the N-terminus does not result in an altered subcellular localization, but in a distinct membrane topology. Insertion in the membrane of endoplasmic reticulum via a double-spanning open hairpin structure allows reorientation to the lumen of the catalytic domain of the protein. In agreement with participation to a different functional unit and supramolecular organization, the protein displays altered heme proximal surface. These data suggest the evolution of divergent C4H enzymes feeding different branches of the phenolic network in seed plants. It shows that specialization required for retention of gene duplicates may result from altered protein topology rather than change in enzyme activity.
    Mots-clés : B3S, LSOD.

  • T. Roach, T. Baur, W. Stöggl, et A. Krieger-Liszkay, « Chlamydomonas reinhardtii responding to high light: A role for 2-propenal (acrolein) », Physiologia Plantarum, 2017.

  • C. Samson, F. Celli, K. Hendriks, M. Zinke, N. Essawy, I. Herrada, A. - A. Arteni, F. - X. Theillet, B. Alpha-Bazin, J. Armengaud, C. Coirault, A. Lange, et S. Zinn-Justin, « Emerin self-assembly mechanism: role of the LEM domain », The FEBS Journal, vol. 284, nᵒ 2, p. 338-352, 2017.
    Mots-clés : B3S, CRYO, INTGEN, PF.

  • Á. Sánchez-Corrionero, I. Sánchez-Vicente, S. González-Pérez, A. Corrales, A. Krieger-Liszkay, Ó. Lorenzo, et J. B. Arellano, « Singlet oxygen triggers chloroplast rupture and cell death in the zeaxanthin epoxidase defective mutant aba1 of Arabidopsis thaliana under high light stress », Journal of Plant Physiology, vol. 216, p. 188-196, 2017.
    Résumé : The two Arabidopsis thaliana mutants, aba1 and max4, were previously identified as sharing a number of co-regulated genes with both the flu mutant and Arabidopsis cell suspension cultures exposed to high light (HL). On this basis, we investigated whether aba1 and max4 were generating high amounts of singlet oxygen ((1)O2) and activating (1)O2-mediated cell death. Thylakoids of aba1 produced twice as much (1)O2 as thylakoids of max4 and wild type (WT) plants when illuminated with strong red light. (1)O2 was measured using the spin probe 2,2,6,6-tetramethyl-4-piperidone hydrochloride. 77-K chlorophyll fluorescence emission spectra of thylakoids revealed lower aggregation of the light harvesting complex II in aba1. This was rationalized as a loss of connectivity between photosystem II (PSII) units and as the main cause for the high yield of (1)O2 generation in aba1. Up-regulation of the (1)O2 responsive gene AAA-ATPase was only observed with statistical significant in aba1 under HL. Two early jasmonate (JA)-responsive genes, JAZ1 and JAZ5, encoding for two repressor proteins involved in the negative feedback regulation of JA signalling, were not up-regulated to the WT plant levels. Chloroplast aggregation followed by chloroplast rupture and eventual cell death was observed by confocal imaging of the fluorescence emission of leaf cells of transgenic aba1 plants expressing the chimeric fusion protein SSU-GFP. Cell death was not associated with direct (1)O2 cytotoxicity in aba1, but rather with a delayed stress response. In contrast, max4 did not show evidence of (1)O2-mediated cell death. In conclusion, aba1 may serve as an alternative model to other (1)O2-overproducing mutants of Arabidopsis for investigating (1)O2-mediated cell death.
    Mots-clés : AAA-ATPase, aba1, B3S, Cell Death, Chloroplast rupture, JAZ repressors, MROP, Singlet oxygen.

  • J. Santolini, F. André, S. Jeandroz, et D. Wendehenne, « Nitric oxide synthase in plants: Where do we stand? », Nitric Oxide, vol. 63, p. 30-38, 2017.

  • P. V. Sauer, J. Timm, D. Liu, D. Sitbon, E. Boeri-Erba, C. Velours, N. Mücke, J. Langowski, F. Ochsenbein, G. Almouzni, et D. Panne, « Insights into the molecular architecture and histone H3-H4 deposition mechanism of yeast Chromatin assembly factor 1 », eLife, vol. 6, mars 2017.
    Mots-clés : AMIG, B3S, PF, PIM.

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