4Z7X

MdbA protein, a thiol-disulfide oxidoreductase from Actinomyces oris.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.180 
  • R-Value Work: 0.124 
  • R-Value Observed: 0.127 

wwPDB Validation   3D Report Full Report


Ligand Structure Quality Assessment 


This is version 1.3 of the entry. See complete history


Literature

A Disulfide Bond-forming Machine Is Linked to the Sortase-mediated Pilus Assembly Pathway in the Gram-positive Bacterium Actinomyces oris.

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

(2015) J Biol Chem 290: 21393-21405

  • DOI: 10.1074/jbc.M115.672253
  • Primary Citation of Related Structures:  
    4Z7X

  • PubMed Abstract: 
  • Export of cell surface pilins in Gram-positive bacteria likely occurs by the translocation of unfolded precursor polypeptides; however, how the unfolded pilins gain their native conformation is presently unknown. Here, we present physiological studies to demonstrate that the FimA pilin of Actinomyces oris contains two disulfide bonds ...

    Export of cell surface pilins in Gram-positive bacteria likely occurs by the translocation of unfolded precursor polypeptides; however, how the unfolded pilins gain their native conformation is presently unknown. Here, we present physiological studies to demonstrate that the FimA pilin of Actinomyces oris contains two disulfide bonds. Alanine substitution of cysteine residues forming the C-terminal disulfide bridge abrogates pilus assembly, in turn eliminating biofilm formation and polymicrobial interaction. Transposon mutagenesis of A. oris yielded a mutant defective in adherence to Streptococcus oralis, and revealed the essential role of a vitamin K epoxide reductase (VKOR) gene in pilus assembly. Targeted deletion of vkor results in the same defects, which are rescued by ectopic expression of VKOR, but not a mutant containing an alanine substitution in its conserved CXXC motif. Depletion of mdbA, which encodes a membrane-bound thiol-disulfide oxidoreductase, abrogates pilus assembly and alters cell morphology. Remarkably, overexpression of MdbA or a counterpart from Corynebacterium diphtheriae, rescues the Δvkor mutant. By alkylation assays, we demonstrate that VKOR is required for MdbA reoxidation. Furthermore, crystallographic studies reveal that A. oris MdbA harbors a thioredoxin-like fold with the conserved CXXC active site. Consistently, each MdbA enzyme catalyzes proper disulfide bond formation within FimA in vitro that requires the catalytic CXXC motif. Because the majority of signal peptide-containing proteins encoded by A. oris possess multiple Cys residues, we propose that MdbA and VKOR constitute a major folding machine for the secretome of this organism. This oxidative protein folding pathway may be a common feature in Actinobacteria.


    Organizational Affiliation

    From the Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas 77030, ton-that.hung@uth.tmc.edu.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
MdbAA, B238Actinomyces orisMutation(s): 0 
Gene Names: mdbAANA_1994
UniProt
Find proteins for A0A0M3KL32 (Actinomyces oris)
Explore A0A0M3KL32 
Go to UniProtKB:  A0A0M3KL32
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
3CX (Subject of Investigation/LOI)
Query on 3CX

Download Ideal Coordinates CCD File 
C [auth A], D [auth B](2S)-3-(cyclohexylamino)-2-hydroxypropane-1-sulfonic acid
C9 H19 N O4 S
INEWUCPYEUEQTN-VIFPVBQESA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
A, BL-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.180 
  • R-Value Work: 0.124 
  • R-Value Observed: 0.127 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 46.88α = 90
b = 66.86β = 90
c = 256.169γ = 90
Software Package:
Software NamePurpose
HKL-3000data scaling
REFMACrefinement
PDB_EXTRACTdata extraction
HKL-3000data reduction
HKL-3000phasing

Structure Validation

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Ligand Structure Quality Assessment  



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesGM094585
National Institutes of Health/National Institute of Dental and Craniofacial Research (NIH/NIDCR)United StatesDE017382
National Institutes of Health/National Institute of Dental and Craniofacial Research (NIH/NIDCR)United StatesDE025015

Revision History  (Full details and data files)

  • Version 1.0: 2015-04-22
    Type: Initial release
  • Version 1.1: 2015-09-09
    Changes: Database references
  • Version 1.2: 2017-09-20
    Changes: Author supporting evidence, Database references, Derived calculations
  • Version 1.3: 2019-12-11
    Changes: Author supporting evidence