|Nuclear Magnetic Resonance of Biomolecules - CNRS URA 2185|
|HEAD||DELEPIERRE Muriel / firstname.lastname@example.org|
|MEMBERS||DR Amorim de Cardoso Gisèle, Babault Nicolas, Caillet-Saguy Célia, Dr Chaffotte Alain, Dr Cordier Florence, Dr Guijarro Inaki, Dr Izadi-Pruneyre Nadia, Dr Lecroisey Anne, Pierre Maisonneuve, Idir Malki, Dr Prochnicka-Chalufour Ada, Simenel Catherine, Terrien Elouan, Dr Wolff Nicolas
Our research area is mainly dedicated to the structure determination of proteins, peptides, nucleic acids and oligosaccharides, in relation to their function but also to molecular interactions studies. The driving force is to adapt NMR techniques to biological problems. How can NMR be used to answer a peculiar question and is NMR the only tool to answer it? Thus, not only modern NMR techniques are employed but also different biophysical approaches are used.
Structural and functional studies of bacterial proteins involved in heme acquisition
Several pathogenic gram-negative bacteria use a heme uptake system involving an extracellular heme-binding protein called hemophore that acquires free or hemoprotein-bound heme and transfers it to its specific outer membrane receptor, via protein-protein interaction. Over the years we have been involved in the molecular characterization of all steps of the mechanism at both structural and functional levels, from hemophore secretion, to heme delivery to the cell via heme uptake and release to the receptor. Particularly hemophores structures in holo and apo forms have been solved and interaction with its receptor characterized. This study is now extended to the understanding of bacterial signalisation in response to stimuli and how this is involved in fondamental procceses such as nutrient transport and pathogenicity.
Structural studies of antigenic determinants recognized by a protective monoclonal antibody in view of developing a vaccine against shigellosis
A possible strategy for human vaccination against shigellosis is to develop synthetic chemically defined vaccines with simple molecules able to mimic the O-SP that would induce the synthesis of protective antibodies. The conformations and the epitopes of oligosaccharides from O-SP of two different serotypes, 5a and 2a, free and bound to protective monoclonal have been characterized.
Structure, function of transcription regulators from hyperthermophile-Archaea viruses
Hyperthermophile-archaea viruses show an exceptional diversity and are very different from viruses that infect bacteria and eukaryotes. Study of the structure and function of proteins that could be involved in transcription regulation, a phenomena essential for infection, has been initiated. The first protein studied, D56, belongs to the virus Sulfolobus islandicus rudivirus (SIRV1) and is expressed throughout the infection cycle of the virus. It interacts specifically with the regions of its own promoter and of the promoter of a neighboring gene. The protein forms a dimer and its structure has been solved whereas its interaction with DNA sequences from its promoter has been characterized. The second protein, Sta1, is a host protein that activates transcription of SIRV1 genes. A model of its structure has been established and validated using NMR.
Structural and functional studies of NEMO, a regulatory protein of the NF-κB pathway
NEMO is a central regulatory protein of the NF-κB signaling pathway, notably involved in early inflammatory and immune responses and in regulation of apoptosis as well as oncogenesis. In order to understand the molecular mechanism by which NEMO participates in NF-κB activation and to facilitate the elaboration of anti-inflammatory and anti-cancer drugs, we are studying the biophysical, structural and functional characteristics of the C-terminal regulatory domains of NEMO and their interactions with biological partners and with small inhibitory molecules.
The control of neuronal death and survival by Rabies virus glycoprotein
Rabies virus (RABV) infects neurons exclusively and causes lethal encephalitis. Pathogenic RABV strains favor neuronal survival, whereas non-pathogen strains lead to neuronal apoptosis. The last four C-terminal amino acids of the G-protein cytoplasmic domain (CytoG) are critical. These residues form a binding site for PDZ domain that differs by one mutation between survival and death G-proteins. We demonstrated that the cytoG of the two strains, pathogenic and non pathogenic, recruit host proteins containing PDZ domains. CytoG of survival strain was found to interact with serine-threonine kinases (MAST), while CytoG of death strain interacts also with the tyrosine phosphatase PTPN4. To understand the structural basis of the PDZ-CytoG complexes the 3D structures of MAST-PDZ and PTPN4-PDZ in complex with the viral peptides and with their natural ligands by NMR and X-rays crystallography.
Prehaud, C., Wolff, N., Terrien, E., Lafage, M., Megret, F., Babault, F., Cordier, F., Tan, G.S., Maitrepierre, E., Menager, P., Chopy, D., Hoos, S., England, P., Delepierre, M., Schell, M.J., Buc, H., Lafon, M. (2010). Attenuation of rabies virulence: take-over by the cytoplasmic domain of the envelope protein. Science Signaling, 3(105) ra5. PMID: 2008624.
Caillet-Saguy, C., Piccioli, M., Turano, P., Izadi-Pruneyre, N., Delepierre, M., Bertini, Y., paragraphLecroisey, A. (2009). Mapping the Interaction between the hemophore HasA and its 98kDa outer membrane receptor HasR in DPC micelles using CRINEPT-TROSY NMR. J. Am. Chem. Soc., 131, 1736-1744. paragraphPMID:19159260
Guillière, F., Peixeiro, N., Kessler, A., Raynal, B., Desnoues, N., Keller, J., Delepierre, M., Pranguishvili, D., Sesonov, G., Guijarro, JI. (2009). Structure, function and targets of the transcriptional regulator SvtR from the hyperthermophilic archaeal virus SIRV1. J. Biol. Chem., 284, 22222-22237. paragraphPMID: 19535331
Aimanianda, V., Clavaud, C., paragraphSimenel, C., Fontaine, T., Delepierre, M., Latge J-P. (2009). Cell wall b-(1,6)-glucan of Saccharomyces cerevisiae structural characterization and in situ synthesis. J. Biol. Chem., 284, 13401-13412. PMID:19279004
Cordier, F., Vinolo, E., Viron, M., Delepierre, M., Agou, F. (2008). Solution structure of NEMO zinc finger and impact of an anhidrotic ectodermal dysplasia with immunodeficiency−related point mutation. J. Mol. Biol., 377, 1419-1432. paragraphPMID:18313693
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