title: Solution structure and backbone dynamics of the reduced form and an oxidized form of E. coli methionine sulfoxide reductase A (MsrA): structural insight of the MsrA catalytic cycle.
abstract: Methionine sulfoxide reductases (Msr) reduce methionine sulfoxide (MetSO)-containing proteins, back to methionine (Met). MsrAs are stereospecific for the S epimer whereas MsrBs reduce the R epimer of MetSO. Although structurally unrelated, the Msrs characterized so far display a similar catalytic mechanism with formation of a sulfenic intermediate on the catalytic cysteine and a concomitant release of Met, followed by formation of at least one intramolecular disulfide bond (between the catalytic and a recycling cysteine), which is then reduced by thioredoxin. In the case of the MsrA from Escherichia coli, two disulfide bonds are formed, i.e. first between the catalytic Cys51 and the recycling Cys198 and then between Cys198 and the second recycling Cys206. Three crystal structures including E. coli and Mycobacterium tuberculosis MsrAs, which, for the latter, possesses only the unique recycling Cys198, have been solved so far. In these structures, the distances between the cysteine residues involved in the catalytic mechanism are too large to allow formation of the intramolecular disulfide bonds. Here structural and dynamical NMR studies of the reduced wild-type and the oxidized (Cys51-Cys198) forms of C86S/C206S MsrA from E. coli have been carried out. The mapping of MetSO substrate-bound C51A MsrA has also been performed. The data support (1) a conformational switch occurring subsequently to sulfenic acid formation and/or Met release that would be a prerequisite to form the Cys51-Cys198 bond and, (2) a high mobility of the C-terminal part of the Cys51-Cys198 oxidized form that would favor formation of the second Cys198-Cys206 disulfide bond.
authors.affiliation: Laboratoire de Chimie Physique Macromoléculaire UMR 7568 CNRS-INPL, Nancy Universités, 1 rue Grandville, B.P. 20451, 54001 Nancy cedex, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Coudevylle
authors.forename: Mathias
authors.initials: M
authors.lastname: Antoine
authors.forename: Sabine
authors.initials: S
authors.lastname: Bouguet-Bonnet
authors.forename: Pierre
authors.initials: P
authors.lastname: Mutzenhardt
authors.forename: Sandrine
authors.initials: S
authors.lastname: Boschi-Muller
authors.forename: Guy
authors.initials: G
authors.lastname: Branlant
authors.forename: Manh-Thong
authors.initials: MT
authors.lastname: Cung
mesh_terms: D001665:Binding Sites; D002384:Catalysis; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry / Q000201:enzymology*; D009682:Magnetic Resonance Spectroscopy; D051150:Methionine Sulfoxide Reductases; D008954:Models, Biological; D009587:Nitrogen Isotopes / Q000737:chemistry; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D012996:Solutions; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D009587:Nitrogen Isotopes; D012996:Solutions; D010088:Oxidoreductases; D051150:Methionine Sulfoxide Reductases; C027219:methionine sulfoxide reductase