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Master thesis

Caractérisation biochimique de la glutarédoxine S16 d’Arabidopsis thaliana

Abstract : Glutaredoxins (Grxs) are small oxidoreductases involved in many cellular processus by reducing glutathionylated proteins and through their ability to bind iron-sulfur clusters. This work aimed at characterizing the molecular mechanisms involved in the redox regulation of the plastidial isoform GrxS16 (class II) of Arabidopsis thaliana. The protein and its cysteinic mutants have been heterologously produced in recombinant form in Escherichia coli and then purified. The analysis of the redox state of the protein in presence of different oxidative compounds reveal that it is more sensitive to both oxidized and nitrosylated glutathione than hydrogen peroxide. Our results have enabled to identify cysteine residues involved in the protein oxidation and to suggest a mechanism of the protein oxidation/reduction. Hence, the cysteine Cys62 is not or not much sensitive to oxidation. The catalytic cysteine Cys158 is firstly oxidized and then, is attacked by the cysteine Cys215, leading to the formation of an intramolecular Cys158-Cys215 disulfide bond. The reduction of AtGrxS16 by plastidial Trxs and not by the classical glutathione-dependent system is related to the redox potential value (- 298 mV) of the disulfide bond that is relatively negative. Finally, we did not highlight a redox regulation of the protein endonuclease activity.
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http://docnum.univ-lorraine.fr/prive/BUS_M_2015_ZANNINI_FLAVIEN.pdf
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https://hal.univ-lorraine.fr/hal-01769037
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Submitted on : Tuesday, April 17, 2018 - 4:27:35 PM
Last modification on : Wednesday, April 18, 2018 - 1:15:21 AM

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  • HAL Id : hal-01769037, version 1

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Flavien Zannini. Caractérisation biochimique de la glutarédoxine S16 d’Arabidopsis thaliana. Sciences de l'environnement. 2015. ⟨hal-01769037⟩

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