5C00

MdbA protein, a thiol-disulfide oxidoreductase from Corynebacterium diphtheriae


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.77 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.162 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

A thiol-disulfide oxidoreductase of the Gram-positive pathogen Corynebacterium diphtheriae is essential for viability, pilus assembly, toxin production and virulence.

Reardon-Robinson, M.E.Osipiuk, J.Jooya, N.Chang, C.Joachimiak, A.Das, A.Ton-That, H.

(2015) Mol.Microbiol. 98: 1037-1050

  • DOI: 10.1111/mmi.13172

  • PubMed Abstract: 
  • The Gram-positive pathogen Corynebacterium diphtheriae exports through the Sec apparatus many extracellular proteins that include the key virulence factors diphtheria toxin and the adhesive pili. How these proteins attain their native conformations a ...

    The Gram-positive pathogen Corynebacterium diphtheriae exports through the Sec apparatus many extracellular proteins that include the key virulence factors diphtheria toxin and the adhesive pili. How these proteins attain their native conformations after translocation as unfolded precursors remains elusive. The fact that the majority of these exported proteins contain multiple cysteine residues and that several membrane-bound oxidoreductases are encoded in the corynebacterial genome suggests the existence of an oxidative protein-folding pathway in this organism. Here we show that the shaft pilin SpaA harbors a disulfide bond in vivo and alanine substitution of these cysteines abrogates SpaA polymerization and leads to the secretion of degraded SpaA peptides. We then identified a thiol-disulfide oxidoreductase (MdbA), whose structure exhibits a conserved thioredoxin-like domain with a CPHC active site. Remarkably, deletion of mdbA results in a severe temperature-sensitive cell division phenotype. This mutant also fails to assemble pilus structures and is greatly defective in toxin production. Consistent with these defects, the ΔmdbA mutant is attenuated in a guinea pig model of diphtheritic toxemia. Given its diverse cellular functions in cell division, pilus assembly and toxin production, we propose that MdbA is a component of the general oxidative folding machine in C. diphtheriae.


    Organizational Affiliation

    Department of Microbiology & Molecular Genetics, University of Texas Health Science Center, Houston, TX, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
MdbA protein
A, B, C, D
208Corynebacterium diphtheriae (strain ATCC 700971 / NCTC 13129 / Biotype gravis)Mutation(s): 0 
Find proteins for Q6NFK7 (Corynebacterium diphtheriae (strain ATCC 700971 / NCTC 13129 / Biotype gravis))
Go to UniProtKB:  Q6NFK7
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
A, B, C, D
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.77 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.162 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 61.532α = 90.00
b = 76.621β = 90.17
c = 72.586γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
PDB_EXTRACTdata extraction
HKL-3000data reduction
HKL-3000phasing
HKL-3000data scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of Dental and Craniofacial ResearchUnited StatesDE025015

Revision History 

  • Version 1.0: 2015-07-15
    Type: Initial release
  • Version 1.1: 2015-09-09
    Type: Database references
  • Version 1.2: 2016-01-27
    Type: Database references
  • Version 1.3: 2017-09-27
    Type: Author supporting evidence, Database references, Derived calculations