3TUF

Structure of the SpoIIQ-SpoIIIAH pore forming complex.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.26 Å
  • R-Value Free: 0.226 
  • R-Value Work: 0.165 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structure of components of an intercellular channel complex in sporulating Bacillus subtilis.

Levdikov, V.M.Blagova, E.V.McFeat, A.Fogg, M.J.Wilson, K.S.Wilkinson, A.J.

(2012) Proc.Natl.Acad.Sci.USA 109: 5441-5445

  • DOI: 10.1073/pnas.1120087109

  • PubMed Abstract: 
  • Following asymmetric cell division during spore formation in Bacillus subtilis, a forespore expressed membrane protein SpoIIQ, interacts across an intercellular space with a mother cell-expressed membrane protein, SpoIIIAH. Their interaction can serv ...

    Following asymmetric cell division during spore formation in Bacillus subtilis, a forespore expressed membrane protein SpoIIQ, interacts across an intercellular space with a mother cell-expressed membrane protein, SpoIIIAH. Their interaction can serve as a molecular "ratchet" contributing to the migration of the mother cell membrane around that of the forespore in a phagocytosis-like process termed engulfment. Upon completion of engulfment, SpoIIQ and SpoIIIAH are integral components of a recently proposed intercellular channel allowing passage from the mother cell into the forespore of factors required for late gene expression in this compartment. Here we show that the extracellular domains of SpoIIQ and SpoIIIAH form a heterodimeric complex in solution. The crystal structure of this complex reveals that SpoIIQ has a LytM-like zinc-metalloprotease fold but with an incomplete zinc coordination sphere and no metal. SpoIIIAH has an α-helical subdomain and a protruding β-sheet subdomain, which mediates interactions with SpoIIQ. SpoIIIAH has sequence and structural homology to EscJ, a type III secretion system protein that forms a 24-fold symmetric ring. Superposition of the structures of SpoIIIAH and EscJ reveals that the SpoIIIAH protomer overlaps with two adjacent protomers of EscJ, allowing us to generate a dodecameric SpoIIIAH ring by using structural homology. Following this superposition, the SpoIIQ chains also form a closed dodecameric ring abutting the SpoIIIAH ring, producing an assembly surrounding a 60 Å channel. The dimensions and organization of the proposed complex suggest it is a plausible model for the extracellular component of a gap junction-like intercellular channel.


    Organizational Affiliation

    Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, United Kingdom.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Stage II sporulation protein Q
B
245Bacillus subtilis (strain 168)Mutation(s): 0 
Gene Names: spoIIQ (ywnI)
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Channels: Intercellular
Protein: 
SpoIIQ-SpoIIIAH Complex
Find proteins for P71044 (Bacillus subtilis (strain 168))
Go to UniProtKB:  P71044
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Stage III sporulation protein AH
A
197Bacillus subtilis (strain 168)Mutation(s): 0 
Gene Names: spoIIIAH
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Channels: Intercellular
Protein: 
SpoIIQ-SpoIIIAH Complex
Find proteins for P49785 (Bacillus subtilis (strain 168))
Go to UniProtKB:  P49785
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.26 Å
  • R-Value Free: 0.226 
  • R-Value Work: 0.165 
  • Space Group: I 2 2 2
Unit Cell:
Length (Å)Angle (°)
a = 78.797α = 90.00
b = 111.088β = 90.00
c = 136.093γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
REFMACrefinement
HKL-2000data collection
SHELXSphasing
HKL-2000data scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-03-14
    Type: Initial release
  • Version 1.1: 2012-07-18
    Type: Database references