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Publications Département B3S


  • 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.

  • 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, RHANDO, Vesiculovirus, VIRO, VIROEM.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • V. Šlouf, V. Kuznetsova, M. Fuciman, C. B. de Carbon, A. Wilson, D. Kirilovsky, et T. Polívka, « Ultrafast spectroscopy tracks carotenoid configurations in the orange and red carotenoid proteins from cyanobacteria », Photosynthesis Research, vol. 131, nᵒ 1, p. 105-117, 2017.
    Résumé : A quenching mechanism mediated by the orange carotenoid protein (OCP) is one of the ways cyanobacteria protect themselves against photooxidative stress. Here, we present a femtosecond spectroscopic study comparing OCP and RCP (red carotenoid protein) samples binding different carotenoids. We confirmed significant changes in carotenoid configuration upon OCP activation reported by Leverenz et al. (Science 348:1463-1466. doi: 10.1126/science.aaa7234 , 2015) by comparing the transient spectra of OCP and RCP. The most important marker of these changes was the magnitude of the transient signal associated with the carotenoid intramolecular charge-transfer (ICT) state. While OCP with canthaxanthin exhibited a weak ICT signal, it increased significantly for canthaxanthin bound to RCP. On the contrary, a strong ICT signal was recorded in OCP binding echinenone excited at the red edge of the absorption spectrum. Because the carbonyl oxygen responsible for the appearance of the ICT signal is located at the end rings of both carotenoids, the magnitude of the ICT signal can be used to estimate the torsion angles of the end rings. Application of two different excitation wavelengths to study OCP demonstrated that the OCP sample contains two spectroscopically distinct populations, none of which is corresponding to the photoactivated product of OCP.
    Mots-clés : B3S, Carotenoids, Cyanobacteria, Intramolecular charge-transfer state, MROP, Non-photochemical quenching, Orange carotenoid protein, Red carotenoid protein, Spectrum Analysis, Ultrafast spectroscopy.

  • O. Tagit et N. Hildebrandt, « Fluorescence Sensing of Circulating Diagnostic Biomarkers Using Molecular Probes and Nanoparticles », ACS Sensors, vol. 2, nᵒ 1, p. 31-45, janv. 2017.

  • A. Talagas, L. Fontaine, L. Ledesma-García, J. Mignolet, I. Li de la Sierra-Gallay, N. Lazar, M. Aumont-Nicaise, M. J. Federle, G. Prehna, P. Hols, et S. Nessler, « Correction: Structural Insights into Streptococcal Competence Regulation by the Cell-to-Cell Communication System ComRS », PLOS Pathogens, vol. 13, nᵒ 2, p. e1006208, févr. 2017.
    Mots-clés : B3S, FAAM, PF, PIM.

  • A. Thurotte, C. Bourcier de Carbon, A. Wilson, L. Talbot, S. Cot, R. López-Igual, et D. Kirilovsky, « The cyanobacterial Fluorescence Recovery Protein has two distinct activities: Orange Carotenoid Protein amino acids involved in FRP interaction », Biochimica et Biophysica Acta (BBA) - Bioenergetics, vol. 1858, nᵒ 4, p. 308-317, 2017.

  • E. Vernhes, M. Renouard, B. Gilquin, P. Cuniasse, D. Durand, P. England, S. Hoos, A. Huet, J. F. Conway, A. Glukhov, V. Ksenzenko, E. Jacquet, N. Nhiri, S. Zinn-Justin, et P. Boulanger, « High affinity anchoring of the decoration protein pb10 onto the bacteriophage T5 capsid », Scientific Reports, vol. 7, p. 41662, févr. 2017.
    Mots-clés : B3S, FAAM, INTGEN, T5PHAG, VIRO.

  • M. Weisslocker-Schaetzel, M. Lembrouk, J. Santolini, et P. Dorlet, « Revisiting the Val/Ile Mutation in Mammalian and Bacterial Nitric Oxide Synthases: A Spectroscopic and Kinetic Study », Biochemistry, vol. 56, nᵒ 5, p. 748-756, févr. 2017.

  • J. Yamamoto, P. Plaza, et K. Brettel, « Repair of (6-4) Lesions in DNA by (6-4) Photolyase: 20 Years of Quest for the Photoreaction Mechanism », Photochemistry and Photobiology, vol. 93, nᵒ 1, p. 51-66, 2017.

  • J. Yu, J. Andreani, F. Ochsenbein, et R. Guerois, « Lessons from (co-)evolution in the docking of proteins and peptides for CAPRI Rounds 28-35: Coevolution in CAPRI Rounds 28-35 », Proteins: Structure, Function, and Bioinformatics, vol. 85, nᵒ 3, p. 378-390, 2017.


  • S. Abel, N. Galamba, E. Karakas, M. Marchi, W. H. Thompson, et D. Laage, « On the Structural and Dynamical Properties of DOPC Reverse Micelles », Langmuir: the ACS journal of surfaces and colloids, 2016.
    Résumé : The structure and dynamics of phospholipid reverse micelles are studied by molecular dynamics. We report all-atom unconstrained simulations of 1,2-dioleoyl-sn-phosphatidylcholine (DOPC) reverse micelles in benzene of increasing sizes, with water-to-surfactant number ratios ranging from W0 = 1 to 16. The aggregation number, i.e., the number of DOPC molecules per reverse micelle, is determined to fit experimental light-scattering measurements of the reverse micelle diameter. The simulated reverse micelles are found to be approximately spherical. Larger reverse micelles (W0 > 4) exhibit a layered structure with a water core and the hydration structure of DOPC phosphate head groups is similar to that found in phospholipid membranes. In contrast, the structure of smaller reverse micelles (W0 ≤ 4) cannot be described as a series of concentric layers successively containing water, surfactant head groups, and surfactant tails, and the head groups are only partly hydrated and frequently present in the core. The dynamics of water molecules within the phospholipid reverse micelles slow down as the reverse micelle size decreases, in agreement with prior studies on AOT and Igepal reverse micelles. However, the average water reorientation dynamics in DOPC reverse micelles is found to be much slower than in AOT and Igepal reverse micelles with the same W0 ratio. This is explained by the smaller water pool and by the stronger interactions between water and the charged head groups, as confirmed by the red-shift of the computed infrared line shape with decreasing W0.
    Mots-clés : B3S, LBMS.

  • J. V. G. Abella, C. Galloni, J. Pernier, D. J. Barry, S. Kjær, M. - F. Carlier, et M. Way, « Isoform diversity in the Arp2/3 complex determines actin filament dynamics », Nature Cell Biology, vol. 18, nᵒ 1, p. 76-86, 2016.
    Résumé : The Arp2/3 complex consists of seven evolutionarily conserved subunits (Arp2, Arp3 and ARPC1-5) and plays an essential role in generating branched actin filament networks during many different cellular processes. In mammals, however, the ARPC1 and ARPC5 subunits are each encoded by two isoforms that are 67% identical. This raises the possibility that Arp2/3 complexes with different properties may exist.  We found that Arp2/3 complexes containing ARPC1B and ARPC5L are significantly better at promoting actin assembly than those with ARPC1A and ARPC5, both in cells and in vitro. Branched actin networks induced by complexes containing ARPC1B or ARPC5L are also disassembled ∼2-fold slower than those formed by their counterparts. This difference reflects the ability of cortactin to stabilize ARPC1B- and ARPC5L- but not ARPC1A- and ARPC5-containing complexes against coronin-mediated disassembly. Our observations demonstrate that the Arp2/3 complex in higher eukaryotes is actually a family of complexes with different properties.
    Mots-clés : ACTIN, Actin Cytoskeleton, Actin-Related Protein 2, Actin-Related Protein 3, Angiopoietins, Animals, B3S, Cell Line, Cortactin, Humans, Mice, Microfilament Proteins, Protein Isoforms.

  • A. M. Acuña, R. Kaňa, M. Gwizdala, J. J. Snellenburg, P. van Alphen, B. van Oort, D. Kirilovsky, R. van Grondelle, et I. H. M. van Stokkum, « A method to decompose spectral changes in Synechocystis PCC 6803 during light-induced state transitions », Photosynthesis Research, vol. 130, nᵒ 1-3, p. 237-249, 2016.
    Résumé : Cyanobacteria have developed responses to maintain the balance between the energy absorbed and the energy used in different pigment-protein complexes. One of the relatively rapid (a few minutes) responses is activated when the cells are exposed to high light intensities. This mechanism thermally dissipates excitation energy at the level of the phycobilisome (PB) antenna before it reaches the reaction center. When exposed to low intensities of light that modify the redox state of the plastoquinone pool, the so-called state transitions redistribute energy between photosystem I and II. Experimental techniques to investigate the underlying mechanisms of these responses, such as pulse-amplitude modulated fluorometry, are based on spectrally integrated signals. Previously, a spectrally resolved fluorometry method has been introduced to preserve spectral information. The analysis method introduced in this work allows to interpret SRF data in terms of species-associated spectra of open/closed reaction centers (RCs), (un)quenched PB and state 1 versus state 2. Thus, spectral differences in the time-dependent fluorescence signature of photosynthetic organisms under varying light conditions can be traced and assigned to functional emitting species leading to a number of interpretations of their molecular origins. In particular, we present evidence that state 1 and state 2 correspond to different states of the PB-PSII-PSI megacomplex.
    Mots-clés : B3S, Cyanobacteria, MROP, Singular value decomposition, Spectrally resolved fluorometry, Time-resolved spectroscopy.

  • A. M. Acuña, J. J. Snellenburg, M. Gwizdala, D. Kirilovsky, R. van Grondelle, et I. H. M. van Stokkum, « Resolving the contribution of the uncoupled phycobilisomes to cyanobacterial pulse-amplitude modulated (PAM) fluorometry signals », Photosynthesis Research, vol. 127, nᵒ 1, p. 91-102, 2016.
    Résumé : Pulse-amplitude modulated (PAM) fluorometry is extensively used to characterize photosynthetic organisms on the slow time-scale (1-1000 s). The saturation pulse method allows determination of the quantum yields of maximal (F(M)) and minimal fluorescence (F(0)), parameters related to the activity of the photosynthetic apparatus. Also, when the sample undergoes a certain light treatment during the measurement, the fluorescence quantum yields of the unquenched and the quenched states can be determined. In the case of cyanobacteria, however, the recorded fluorescence does not exclusively stem from the chlorophyll a in photosystem II (PSII). The phycobilins, the pigments of the cyanobacterial light-harvesting complexes, the phycobilisomes (PB), also contribute to the PAM signal, and therefore, F(0) and F(M) are no longer related to PSII only. We present a functional model that takes into account the presence of several fluorescent species whose concentrations can be resolved provided their fluorescence quantum yields are known. Data analysis of PAM measurements on in vivo cells of our model organism Synechocystis PCC6803 is discussed. Three different components are found necessary to fit the data: uncoupled PB (PB(free)), PB-PSII complexes, and free PSI. The free PSII contribution was negligible. The PB(free) contribution substantially increased in the mutants that lack the core terminal emitter subunits allophycocyanin D or allophycocyanin F. A positive correlation was found between the amount of PB(free) and the rate constants describing the binding of the activated orange carotenoid protein to PB, responsible for non-photochemical quenching.
    Mots-clés : B3S, Computer Simulation, Cyanobacteria, Fluorescence, Fluorescence quantum yield, Fluorometry, Models, Biological, MROP, Mutation, Non-photochemical quenching, Photosystem I Protein Complex, Photosystem II Protein Complex, Phycobilisome, Phycobilisomes, Phycocyanin, Protein Subunits, Pulse-amplitude modulated (PAM) fluorometry, Synechocystis, Time Factors.

  • S. Ahmad, L. Pecqueur, B. Dreier, D. Hamdane, M. Aumont-Nicaise, A. Plückthun, M. Knossow, et B. Gigant, « Destabilizing an interacting motif strengthens the association of a designed ankyrin repeat protein with tubulin », Scientific Reports, vol. 6, p. 28922, juill. 2016.
    Mots-clés : B3S, MIKICA, PF, PIM.

  • D. Akhmetzyanov, H. Y. V. Ching, V. Denysenkov, P. Demay-Drouhard, H. C. Bertrand, L. C. Tabares, C. Policar, T. F. Prisner, et S. Un, « RIDME spectroscopy on high-spin Mn(2+) centers », Physical chemistry chemical physics: PCCP, vol. 18, nᵒ 44, p. 30857-30866, 2016.
    Résumé : Pulsed EPR dipolar spectroscopy is a powerful tool for determining the structure and conformational dynamics of biological macromolecules, as it allows precise measurements of distances in the range of 1.5-10 nm. Utilization of high-spin Mn(2+) species as spin probes for distance measurements is of significant interest, because they are biologically compatible and endogenous in numerous biological systems. However, to date dipolar spectroscopy experiments with this kind of species have been underexplored. Here we present pulsed electron electron double resonance (PELDOR also called DEER) and relaxation-induced dipolar modulation enhancement (RIDME) experiments, which have been performed at W-band (94 GHz) and J-band frequencies (263 GHz) on a bis-MnDOTA (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) model system. The distances obtained from these experiments are in good agreement with predictions. RIDME experiments reveal a significantly higher modulation depth compared to PELDOR, which is an important consideration for biological samples. These experiments also feature higher harmonics of the dipolar coupling frequency due to effective multiple-quantum relaxation of high-spin Mn(2+) as well as the multiple-component background function. Harmonics of the dipolar coupling frequency were taken into account by including additional terms in the kernel function of Tikhonov regularization analysis.
    Mots-clés : B3S, BHFMR.

  • A. Akil, J. Peng, M. Omrane, C. Gondeau, C. Desterke, M. Marin, H. Tronchère, C. Taveneau, S. Sar, P. Briolotti, S. Benjelloun, A. Benjouad, P. Maurel, V. Thiers, S. Bressanelli, D. Samuel, C. Bréchot, et A. Gassama-Diagne, « Septin 9 induces lipid droplets growth by a phosphatidylinositol-5-phosphate and microtubule-dependent mechanism hijacked by HCV », Nature Communications, vol. 7, p. 12203, juill. 2016.

  • A. Araye, A. Goudet, J. Barbier, S. Pichard, B. Baron, P. England, J. Pérez, S. Zinn-Justin, A. Chenal, et D. Gillet, « Correction: The Translocation Domain of Botulinum Neurotoxin A Moderates the Propensity of the Catalytic Domain to Interact with Membranes at Acidic pH », PLOS ONE, vol. 11, nᵒ 8, p. e0161743, août 2016.

  • A. Araye, A. Goudet, J. Barbier, S. Pichard, B. Baron, P. England, J. Pérez, S. Zinn-Justin, A. Chenal, et D. Gillet, « The Translocation Domain of Botulinum Neurotoxin A Moderates the Propensity of the Catalytic Domain to Interact with Membranes at Acidic pH », PLOS ONE, vol. 11, nᵒ 4, p. e0153401, avr. 2016.

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