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Mécanisme, catalyse et spécificité structurale des méthionine sulfoxyde réductases de classe B et la protéine PilB de Neisseria meningitidis

Abstract : Ubiquitous enzyme methionine sulfoxide reductases (Msrs) are involved in oxidative stress resistance, aging process but also in bacteria pathogenicity like for Neisseria genius. The two Msrs classes : MsrA and MsrB structural-unrelated catalyze the reduction of the two stereoisomeric forms R and S of the sulfoxide function from the methionine sulfoxide. They share a similar three-step chemical mechanism including formation of a sulfenic acid intermediate following by intramolecular disulfide bond formation, reduced in the last step by the thioredoxin (Trx). The structure function studies are conduced to 1) characterization of active site amino acids involved in substrate recognition and reductase step catalysis leading to sulfenic acid formation in Neisseria meningitidis (N. meningitidis) MsrB, we have proposed a scenario for the reductase step with a major role of the acid / base catalyst His 103 2) characterization of different MsrB sub-classes mechanisms, Xanthomonas campestris MsrB present a Cys 31 located in a flexible loop compare to the Cys 63 from N. meningitidis MsrB also located in a flexible loop, the Mycoplasma pulmonis MsrB don't posses recycling Cys; and 3) characterization of the N. meningitidis PilB, a three domains protein located in the periplasm, PilB possess MsrA and MsrB activities, and a oxydoreductase activity carried by the N-terminal domain, moreover this domain can reduced the oxidized MsrA and MsrB domains.
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Theses
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http://docnum.univ-lorraine.fr/prive/SCD_T_2007_0075_NEIERS.pdf
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https://hal.univ-lorraine.fr/tel-01747006
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Submitted on : Thursday, March 29, 2018 - 10:49:23 AM
Last modification on : Friday, February 26, 2021 - 3:02:02 PM

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  • HAL Id : tel-01747006, version 1

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Fabrice Neiers. Mécanisme, catalyse et spécificité structurale des méthionine sulfoxyde réductases de classe B et la protéine PilB de Neisseria meningitidis. Biochimie, Biologie Moléculaire. Université Henri Poincaré - Nancy 1, 2007. Français. ⟨NNT : 2007NAN10075⟩. ⟨tel-01747006⟩

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