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LA RIBONUCLEOTIDE REDUCTASE ANAEROBIE D'ESCHERICHIA COLI, UNE PROTEINE A ZINC. IMPORTANCE DU SITE METALLIQUE POUR LA STRUCTURE ET L'ACTIVITE DE L'ENZYME.

Abstract : RIBONUCLEOTIDE REDUCTASES (RNRS) ARE CRITICAL ENZYMES FOR THE DE NOVO SYNTHESIS OF DNA IN ALL ORGANISMS. FOR ITS ANAEROBIC GROWTH, ESCHERICHIA COLI DEPENDS ON A CLASS III RNR, WHICH HARBORS IN ITS ACTIVE FORM AN OXYGEN-SENSITIVE FREE RADICAL LOCATED ON THE GLY681 RESIDUE, THE FORMATION OF WHICH INVOLVES THE CONCERTED ACTION OF FOUR COMPONENTS: AN ACTIVATING IRON-SULFUR PROTEIN, S-ADENOSYLMETHIONINE, DITHIOTHREITOL (DTT), AND A REDUCING SYSTEM. A ZN(CYS)4 CENTER HAS RECENTLY BEEN FOUND IN THE C-TERMINAL REGION OF THE CRYSTAL STRUCTURE OF THE RNR FROM BACTERIOPHAGE T4. IN THIS WORK WE DEFINE NEW CONDITIONS ALLOWING FOR THE PREPARATION OF A HIGH SPECIFIC ACTIVITY REDUCTASE. WE SHOW THAT THE ZINC SITE CONTROLS THE STRUCTURATION OF THE CTER LOOP CARRYING THE RADICAL SITE. FINALLY WE DEMONSTRATE THAT DTT IS NOT ESSENTIAL FOR RADICAL FORMATION BUT RATHER ACTS ON RADICAL TRANSFER REACTIONS BETWEEN GLY· AND THE SUBSTRATE.
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https://tel.archives-ouvertes.fr/tel-00122711
Contributor : Florence Luttringer <>
Submitted on : Thursday, January 4, 2007 - 2:33:34 PM
Last modification on : Friday, November 6, 2020 - 4:12:36 AM
Long-term archiving on: : Wednesday, April 7, 2010 - 1:41:18 AM

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  • HAL Id : tel-00122711, version 1

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Florence Luttringer. LA RIBONUCLEOTIDE REDUCTASE ANAEROBIE D'ESCHERICHIA COLI, UNE PROTEINE A ZINC. IMPORTANCE DU SITE METALLIQUE POUR LA STRUCTURE ET L'ACTIVITE DE L'ENZYME.. Biochimie [q-bio.BM]. Université Joseph-Fourier - Grenoble I, 2006. Français. ⟨tel-00122711⟩

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