|Nuclear Magnetic Resonance of Biomolecules - CNRS URA 2185|
|HEAD||Muriel DELEPIERRE, Dr / firstname.lastname@example.org|
|MEMBERS||Muriel DELEPIERRE, DR, Anne LECROISEY, CR, Alain CHAFFOTTE, DR, Nicolas WOLFF, CR, Nadia IZADI, CR, Florence CORDIER, CR, Josaba Inaki GUIJARRO ARRILLAGA, CR
Ada PROCHNICKA-CHALUFOUR, Dr,Catherine SIMENEL, Karine WECKER, Dr
Célia CAILLET-SAGUY , Dr, François-Xavier THEILLET, Florence GUILLIERE , Nicolas BABAULT, Elouan TERRIEN
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 biological 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 hemophore’s structures in holo and apo forms have been solved and interaction with its receptor characterized.
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.
Structural study of proteins involved in the late transcription program in the forespore
Sporulation is a primitive developmental process carried out by Bacilli and Clostridia in response to nutrient starvation, involving the formation of a forespore and a mother cell. Each cell implements an early and a late transcription program under the control of proteins associated with RNA polymerase, the sigma factors. The late forespore sigma factor (sigma-G) is maintained in an inactive form by a recently identified inhibitor (Gin) and its activity is released after complete engulfment of the forespore by the mother cell. To understand the mechanism by which Gin inhibits sigma-G at a specific developmental stage, we are studying the biophysical and structural properties of Gin and its interaction with sigma-G.
Keywords: Biophysique, RMN, structure, interactions, biomolécules, modélisation moléculaire
WEST, N.P., SANSONETTI, P., MOUNIER, J., EXLEY, R.M., PARSOT, C., GUADAGNINI, S., PREVOST, M-C., PROCHNICKA-CHALUFOUR, A., DELEPIERRE, M., TANGUY, M., TANG, C.M. 2005 Optimization of virulence functions through glucolysation of Shigella LPS. Science 307(5713), 1313-1317.
CLEMENT, M-J., FORTUNE,A., PHALIPON, A., MARCEL-PEYRE, V., SIMENEL, C., IMBERTY, A., DELEPIERRE, M., MULARD, L. 2006 Towards a better understanding of the basis of molecular mimicry of polysaccharide antigens by peptides : the example of Shigella flexneri 5a. Journal of Biological Chemistry 281, 2317-2332
CAILLET, C., DELEPIERRE, M., LECROISEY, A., BERTINI, I., PICCIOLI, M., TURANO, P. 2006 Direct Detected 13C NMR to investigate the iron(III) hemophore HasA. Journal of American Chemical Society 128, 150-158
KESSLER, A., SEZONOV, G., GUIJARRO, J.I., DESNOUES, N., ROSE, T., DELEPIERRE, M., BELL, S., PRANGISHVILI, D. 2006 A novel archaeal regulatory protein, Sta1, activates transcription from viral promoters" Nucleic Acid Research 34, 4837-4845
CZJZEK,M., LETOFFE, S., WANDERSMAN, C., DELEPIERRE, M., LECROISEY, A., IZADI-PRUNEYRE, N. 2007. The crystal structure of the secreted dimeric form of the hemophore HasA reveals a domain swapping with an exchanged heme ligand. Journal of Molecular Biology 365, 1176-1186
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