TubR from Bacillus megaterium pBM400

Experimental Data Snapshot

  • Resolution: 3.50 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.186 
  • R-Value Observed: 0.188 

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This is version 1.2 of the entry. See complete history


Superstructure of the Centromeric Complex of Tubzrc Plasmid Partitioning Systems.

Aylett, C.H.S.Lowe, J.

(2012) Proc Natl Acad Sci U S A 109: 16522

  • DOI: https://doi.org/10.1073/pnas.1210899109
  • Primary Citation of Related Structures:  
    4ASN, 4ASO, 4ASS

  • PubMed Abstract: 

    Bacterial plasmid partitioning systems segregate plasmids into each daughter cell. In the well-understood ParMRC plasmid partitioning system, adapter protein ParR binds to centromere parC, forming a helix around which the DNA is externally wrapped. This complex stabilizes the growth of a filament of actin-like ParM protein, which pushes the plasmids to the poles. The TubZRC plasmid partitioning system consists of two proteins, tubulin-like TubZ and TubR, and a DNA centromere, tubC, which perform analogous roles to those in ParMRC, despite being unrelated in sequence and structure. We have dissected in detail the binding sites that comprise Bacillus thuringiensis tubC, visualized the TubRC complex by electron microscopy, and determined a crystal structure of TubR bound to the tubC repeat. We show that the TubRC complex takes the form of a flexible DNA-protein filament, formed by lateral coating along the plasmid from tubC, the full length of which is required for the successful in vitro stabilization of TubZ filaments. We also show that TubR from Bacillus megaterium forms a helical superstructure resembling that of ParR. We suggest that the TubRC DNA-protein filament may bind to, and stabilize, the TubZ filament by forming such a ring-like structure around it. The helical superstructure of this TubRC may indicate convergent evolution between the actin-containing ParMRC and tubulin-containing TubZRC systems.

  • Organizational Affiliation

    Medical Research Council Laboratory of Molecular Biology, Division of Structural Studies, Cambridge, United Kingdom.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C
101Priestia megateriumMutation(s): 0 
Find proteins for Q848W2 (Priestia megaterium (strain ATCC 12872 / QMB1551))
Explore Q848W2 
Go to UniProtKB:  Q848W2
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ848W2
Sequence Annotations
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
Query on MSE
A, B, C
Experimental Data & Validation

Experimental Data

  • Resolution: 3.50 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.186 
  • R-Value Observed: 0.188 
  • Space Group: H 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 179.845α = 90
b = 179.845β = 90
c = 114.342γ = 120
Software Package:
Software NamePurpose
XDSdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-10-03
    Type: Initial release
  • Version 1.1: 2012-10-24
    Changes: Database references
  • Version 1.2: 2019-05-08
    Changes: Data collection, Derived calculations, Experimental preparation, Other