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Grenoble, France

Riss A.,University of Strasbourg | Riss A.,Millipore | Scheer E.,University of Strasbourg | Joint M.,University of Strasbourg | And 6 more authors.
Journal of Biological Chemistry | Year: 2015

Background: Histone acetyltransferases (HATs) incorporated in large multiprotein complexes are involved in a wide variety of cellular processes, including transcription regulation. Results: Subunits of HAT complexes enhance the enzymatic activity of their catalytic subunits. Conclusion: The activity, but not the specificity of HAT complexes, is stimulated by the corresponding subunits. Significance: We gained important insights into histone acetylation function and specificity of HAT complexes. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Thierry E.,University Grenoble alpes | Thierry E.,French National Center for Scientific Research | Brennich M.,European Synchrotron Radiation Facility | Round A.,EMBL Grenoble Outstation | And 5 more authors.
Virus Genes | Year: 2015

The helicase–primase complex is part of the lytic DNA replication machinery of herpesviruses, but up to now, almost nothing is known about its structure. For Epstein–Barr virus it consists in the helicase BBLF4, the primase BSLF1 and the accessory protein BBLF2/3. The accessory protein shows only weak sequence homology within the herpesvirus family but may be related to an inactive B-family polymerase. BSLF1 belongs to the archaeo-eukaryotic primase family, whereas the helicase BBLF4 has been related either to Dda helicases of caudovirales or to Pif1 helicases. We produced the helicase–primase complex in insect cells using a baculovirus coding for all three proteins simultaneously. The soluble monomeric helicase–primase complex containing the three proteins with 1:1:1 stoichiometry showed ATPase activity, which is strongly stimulated in the presence of ssDNA oligomers. Furthermore, we expressed BBLF2/3 as soluble monomeric protein and performed small-angle X-ray scattering experiments which yielded an envelope whose shape is compatible with B-family polymerases. © 2015, Springer Science+Business Media New York.

Guedich S.,University of Strasbourg | Puffer-Enders B.,University of Strasbourg | Baltzinger M.,University of Strasbourg | Hoffmann G.,EMBL Grenoble Outstation | And 7 more authors.
RNA Biology | Year: 2016

Riboswitches are non-coding elements upstream or downstream of mRNAs that, upon binding of a specific ligand, regulate transcription and/or translation initiation in bacteria, or alternative splicing in plants and fungi. We have studied thiamine pyrophosphate (TPP) riboswitches regulating translation of thiM operon and transcription and translation of thiC operon in E. coli, and that of THIC in the plant A. thaliana. For all, we ascertained an induced-fit mechanism involving initial binding of the TPP followed by a conformational change leading to a higher-affinity complex. The experimental values obtained for all kinetic and thermodynamic parameters of TPP binding imply that the regulation by A. thaliana riboswitch is governed by mass-action law, whereas it is of kinetic nature for the two bacterial riboswitches. Kinetic regulation requires that the RNA polymerase pauses after synthesis of each riboswitch aptamer to leave time for TPP binding, but only when its concentration is sufficient. A quantitative model of regulation highlighted how the pausing time has to be linked to the kinetic rates of initial TPP binding to obtain an ON/OFF switch in the correct concentration range of TPP. We verified the existence of these pauses and the model prediction on their duration. Our analysis also led to quantitative estimates of the respective efficiency of kinetic and thermodynamic regulations, which shows that kinetically regulated riboswitches react more sharply to concentration variation of their ligand than thermodynamically regulated riboswitches. This rationalizes the interest of kinetic regulation and confirms empirical observations that were obtained by numerical simulations. © 2016 The Author(s). Published with license by Taylor & Francis Group, LLC

De Sanctis D.,European Synchrotron Radiation Facility | Beteva A.,European Synchrotron Radiation Facility | Caserotto H.,European Synchrotron Radiation Facility | Dobias F.,European Synchrotron Radiation Facility | And 15 more authors.
Journal of Synchrotron Radiation | Year: 2012

ID29 is an ESRF undulator beamline with a routinely accessible energy range of between 20.0 keV and 6.0 keV (λ = 0.62 Å to 2.07 Å) dedicated to the use of anomalous dispersion techniques in macromolecular crystallography. Since the beamline was first commissioned in 2001, ID29 has, in order to provide an improved service to both its academic and proprietary users, been the subject of almost continuous upgrade and refurbishment. It is now also the home to the ESRF Cryobench facility, ID29S. Here, the current status of the beamline is described and plans for its future are briefly outlined. © 2012 International Union of Crystallography.

Reuter M.,EMBL Grenoble Outstation | Pillai R.S.,EMBL Grenoble Outstation
Methods in Molecular Biology | Year: 2014

Small RNAs associate with members of the Argonaute family to function in gene regulation, transposon control, and creation of silent chromatin domains. In this partnership, small RNAs act as guides for the bound Argonaute and other associated proteins. Complementary base pairing of small RNAs to target nucleic acid molecules allow specificity for the small RNA-mediated functions. One key activity of some Argonaute protein family members is their small RNA-guided endonuclease activity called Slicer action. Here we describe a protocol that can be used to probe slicer activity in endogenous Piwi complexes isolated from mouse testes. © 2014 Springer Science+Business Media, LLC.

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