Corynebacterium diphtheriae methionine sulfoxide reductase B (MsrB) solution structure - reduced form

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

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Methionine sulfoxide reductase B fromCorynebacterium diphtheriaecatalyzes sulfoxide reduction via an intramolecular disulfide cascade.

Tossounian, M.A.Khanh Truong, A.C.Buts, L.Wahni, K.Mourenza, A.Leermakers, M.Vertommen, D.Mateos, L.M.Volkov, A.N.Messens, J.

(2020) J Biol Chem 295: 3664-3677

  • DOI: https://doi.org/10.1074/jbc.RA119.012438
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Corynebacterium diphtheriae is a human pathogen that causes diphtheria. In response to immune system-induced oxidative stress, C. diphtheriae expresses antioxidant enzymes, among which are methionine sulfoxide reductase (Msr) enzymes, which are critical for bacterial survival in the face of oxidative stress. Although some aspects of the catalytic mechanism of the Msr enzymes have been reported, several details still await full elucidation. Here, we solved the solution structure of C. diphtheriae MsrB (Cd-MsrB) and unraveled its catalytic and oxidation-protection mechanisms. Cd-MsrB catalyzes methionine sulfoxide reduction involving three redox-active cysteines. Using NMR heteronuclear single-quantum coherence spectra, kinetics, biochemical assays, and MS analyses, we show that the conserved nucleophilic residue Cys-122 is S -sulfenylated after substrate reduction, which is then resolved by a conserved cysteine, Cys-66, or by the nonconserved residue Cys-127. We noted that the overall structural changes during the disulfide cascade expose the Cys-122-Cys-66 disulfide to recycling through thioredoxin. In the presence of hydrogen peroxide, Cd-MsrB formed reversible intra- and intermolecular disulfides without losing its Cys-coordinated Zn 2+ , and only the nonconserved Cys-127 reacted with the low-molecular-weight (LMW) thiol mycothiol, protecting it from overoxidation. In summary, our structure-function analyses reveal critical details of the Cd-MsrB catalytic mechanism, including a major structural rearrangement that primes the Cys-122-Cys-66 disulfide for thioredoxin reduction and a reversible protection against excessive oxidation of the catalytic cysteines in Cd-MsrB through intra- and intermolecular disulfide formation and S -mycothiolation.

  • Organizational Affiliation

    VIB-VUB Center for Structural Biology, B-1050 Brussels, Belgium; Brussels Center for Redox Biology, B-1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussels, B-1050 Brussels, Belgium.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Peptide-methionine (R)-S-oxide reductase156Corynebacterium diphtheriaeMutation(s): 0 
Gene Names: msrBB11Q_01469B1A51_07985BT093_04380
Find proteins for Q6NGV7 (Corynebacterium diphtheriae (strain ATCC 700971 / NCTC 13129 / Biotype gravis))
Explore Q6NGV7 
Go to UniProtKB:  Q6NGV7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ6NGV7
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on ZN

Download Ideal Coordinates CCD File 
B [auth A]ZINC ION
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Research Foundation - Flanders (FWO)Belgium1508316N

Revision History  (Full details and data files)

  • Version 1.0: 2020-02-05
    Type: Initial release
  • Version 1.1: 2020-03-25
    Changes: Database references