34 research outputs found

    ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider

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    Santé globale, santé de première ligne, santé communautaire (présentation du projet de "la case de santé" à Toulouse)

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    Next to define health concepts of primary care, global health, community health and local observatory of health, we present a health center project in Toulouse (France) with an associative statue: La case de santé . This organization will be managed by a multi-field health team non hierarchical (general practitioner, wise woman, nurse, coordinator) , in collaboration with an users s committee. The organization centers it s action on four Toulouse s neighbours whom represent the population diversity of the town.It poses two principles: the acquisition by the health team of knowledges and practices allowing to answer in best at the first care requests, with an independent formation which avoids any influence from industrial or corporatist interest; and the individual systemic approach to try to understand and act on the nonmedical determinants of health (social, economical ) .TOULOUSE3-BU Santé-Centrale (315552105) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

    Crystal structures of complexes of the small ribosomal subunit with tetracycline, edeine and IF3

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    The small ribosomal subunit is responsible for the decoding of genetic information and plays a key role in the initiation of protein synthesis. We analyzed by X-ray crystallography the structures of three different complexes of the small ribosomal subunit of Thermus thermophilus with the A-site inhibitor tetracycline, the universal initiation inhibitor edeine and the C-terminal domain of the translation initiation factor IF3. The crystal structure analysis of the complex with tetracycline revealed the functionally important site responsible for the blockage of the A-site. Five additional tetracycline sites resolve most of the controversial biochemical data on the location of tetracycline. The interaction of edeine with the small subunit indicates its role in inhibiting initiation and shows its involvement with P-site tRNA. The location of the C-terminal domain of IF3, at the solvent side of the platform, sheds light on the formation of the initiation complex, and implies that the anti-association activity of IF3 is due to its influence on the conformational dynamics of the small ribosomal subunit

    The structure of ribosome-lankacidin complex reveals ribosomal sites for synergistic antibiotics

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    Crystallographic analysis revealed that the 17-member polyketide antibiotic lankacidin produced by Streptomyces rochei binds at the peptidyl transferase center of the eubacterial large ribosomal subunit. Biochemical and functional studies verified this finding and showed interference with peptide bond formation. Chemical probing indicated that the macrolide lankamycin, a second antibiotic produced by the same species, binds at a neighboring site, at the ribosome exit tunnel. These two antibiotics can bind to the ribosome simultaneously and display synergy in inhibiting bacterial growth. The binding site of lankacidin and lankamycin partially overlap with the binding site of another pair of synergistic antibiotics, the streptogramins. Thus, at least two pairs of structurally dissimilar compounds have been selected in the course of evolution to act synergistically by targeting neighboring sites in the ribosome. These results underscore the importance of the corresponding ribosomal sites for development of clinically relevant synergistic antibiotics and demonstrate the utility of structural analysis for providing new directions for drug discovery

    Ribosomal crystallography: a flexible nucleotide anchoring tRNA translocation, facilitates peptide-bond formation, chirality discrimination and antibiotics synergism

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    AbstractThe linkage between internal ribosomal symmetry and transfer RNA (tRNA) positioning confirmed positional catalysis of amino-acid polymerization. Peptide bonds are formed concurrently with tRNA-3′end rotatory motion, in conjunction with the overall messenger RNA (mRNA)/tRNA translocation. Accurate substrate alignment, mandatory for the processivity of protein biosynthesis, is governed by remote interactions. Inherent flexibility of a conserved nucleotide, anchoring the rotatory motion, facilitates chirality discrimination and antibiotics synergism. Potential tRNA interactions explain the universality of the tRNA CCA-end and P-site preference of initial tRNA. The interactions of protein L2 tail with the symmetry-related region periphery explain its conservation and its contributions to nascent chain elongation
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