EFFETS DES RADIATIONS IONISANTES SUR DES COMPLEXES
ADN-PROTÉINE

Abstract : The radio-induced destruction of DNA-protein complexes may have serious consequences for systems implicated in important cellular functions. The first system which has been studied is the lactose operon system, that regulates gene expression in Escherichia coli. First of all, the repressor-operator complex is destroyed after irradiation of the complex or of the protein alone. The damaging of the domain of repressor binding to DNA (headpiece) has been demonstrated and studied from the point of view of peptide chain integrity, conformation and amino acids damages. Secondly, dysfunctions of the in vitro induction of an irradiated repressor-unirradiated DNA complex have been observed. These perturbations, due to a decrease of the number of inducer binding sites, are correlated to the damaging of tryptophan residues. Moreover, the inducer protects the repressor when they are irradiated together, both by acting as a scavenger in the bulk, and by the masking of its binding site on the protein. The second studied system is formed by Fpg (for Formamidopyrimidine glycosylase), a DNA repair protein and a DNA with an oxidative lesion. The results show that irradiation disturbs the repair both by decreasing its efficiency of DNA lesion recognition and binding, and by altering its enzymatic activity
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Submitted on : Wednesday, January 18, 2006 - 3:29:07 PM
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  • HAL Id : tel-00011412, version 1

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Nathalie Gillard. EFFETS DES RADIATIONS IONISANTES SUR DES COMPLEXES
ADN-PROTÉINE. domain_other. Université d'Orléans, 2005. Français. ⟨tel-00011412⟩

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