6AN5

Crystal Structure of The Nucelotide Binding Domain of an O-antigen polysaccharide ABC-transporter


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.51 Å
  • R-Value Free: 0.305 
  • R-Value Work: 0.245 
  • R-Value Observed: 0.248 

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This is version 1.2 of the entry. See complete history


Literature

Architecture of a channel-forming O-antigen polysaccharide ABC transporter.

Bi, Y.Mann, E.Whitfield, C.Zimmer, J.

(2018) Nature 553: 361-365

  • DOI: 10.1038/nature25190
  • Primary Citation of Related Structures:  
    6AN5, 6AMX, 6OIH

  • PubMed Abstract: 
  • O-antigens are cell surface polysaccharides of many Gram-negative pathogens that aid in escaping innate immune responses. A widespread O-antigen biosynthesis mechanism involves the synthesis of the lipid-anchored polymer on the cytosolic face of the inner membrane, followed by transport to the periplasmic side where it is ligated to the lipid A core to complete a lipopolysaccharide molecule ...

    O-antigens are cell surface polysaccharides of many Gram-negative pathogens that aid in escaping innate immune responses. A widespread O-antigen biosynthesis mechanism involves the synthesis of the lipid-anchored polymer on the cytosolic face of the inner membrane, followed by transport to the periplasmic side where it is ligated to the lipid A core to complete a lipopolysaccharide molecule. In this pathway, transport to the periplasm is mediated by an ATP-binding cassette (ABC) transporter, called Wzm-Wzt. Here we present the crystal structure of the Wzm-Wzt homologue from Aquifex aeolicus in an open conformation. The transporter forms a transmembrane channel that is sufficiently wide to accommodate a linear polysaccharide. Its nucleotide-binding domain and a periplasmic extension form 'gate helices' at the cytosolic and periplasmic membrane interfaces that probably serve as substrate entry and exit points. Site-directed mutagenesis of the gates impairs in vivo O-antigen secretion in the Escherichia coli prototype. Combined with a closed structure of the isolated nucleotide-binding domains, our structural and functional analyses suggest a processive O-antigen translocation mechanism, which stands in contrast to the classical alternating access mechanism of ABC transporters.


    Organizational Affiliation

    Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
ABC transporterA, B242Aquifex aeolicus VF5Mutation(s): 0 
Gene Names: abcT4aq_1094
Find proteins for O67181 (Aquifex aeolicus (strain VF5))
Explore O67181 
Go to UniProtKB:  O67181
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.51 Å
  • R-Value Free: 0.305 
  • R-Value Work: 0.245 
  • R-Value Observed: 0.248 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 97.21α = 90
b = 97.21β = 90
c = 103.69γ = 120
Software Package:
Software NamePurpose
Aimlessdata scaling
PHENIXrefinement
PDB_EXTRACTdata extraction
Aimlessdata reduction
PHENIXphasing

Structure Validation

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Entry History 

Deposition Data

  • Deposited Date: 2017-08-12 
  • Released Date: 2017-11-29 
  • Deposition Author(s): Zimmer, J., Bi, Y.

Revision History  (Full details and data files)

  • Version 1.0: 2017-11-29
    Type: Initial release
  • Version 1.1: 2018-01-24
    Changes: Database references
  • Version 1.2: 2018-01-31
    Changes: Database references