The structure of the kdo-capped saccharide binding subunit of the O-12 specific ABC transporter, Wzt

Experimental Data Snapshot

  • Resolution: 1.70 Å
  • R-Value Free: 0.215 
  • R-Value Work: 0.183 
  • R-Value Observed: 0.185 

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The Klebsiella pneumoniae O12 ATP-binding Cassette (ABC) Transporter Recognizes the Terminal Residue of Its O-antigen Polysaccharide Substrate.

Mann, E.Mallette, E.Clarke, B.R.Kimber, M.S.Whitfield, C.

(2016) J Biol Chem 291: 9748-9761

  • DOI: https://doi.org/10.1074/jbc.M116.719344
  • Primary Citation of Related Structures:  
    5HNO, 5HNP

  • PubMed Abstract: 

    Export of the Escherichia coli serotype O9a O-antigenic polysaccharides (O-PS) involves an ATP-binding cassette (ABC) transporter. The process requires a non-reducing terminal residue, which is recognized by a carbohydrate-binding module (CBM) appended to the C terminus of the nucleotide-binding domain of the transporter. Here, we investigate the process in Klebsiella pneumoniae serotype O12 (and Raoultella terrigena ATCC 33257). The O12 polysaccharide is terminated at the non-reducing end by a β-linked 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) residue. The O12 ABC transporter also binds its cognate O-PS via a CBM, and export is dependent on the presence of the terminal β-Kdo residue. The overall structural architecture of the O12 CBM resembles the O9a prototype, but they share only weak sequence similarity, and the putative binding pocket for the O12 glycan is different. Removal of the CBM abrogated O-PS transport, but export was restored when the CBM was expressed in trans with the mutant CBM-deficient ABC transporter. These results demonstrate that the CBM-mediated substrate-recognition mechanism is evolutionarily conserved and can operate with glycans of widely differing structures.

  • Organizational Affiliation

    From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ABC type transport system putative ATP binding protein
A, B, C
190Raoultella terrigenaMutation(s): 0 
Gene Names: wzt
Find proteins for Q6U8B1 (Raoultella terrigena)
Explore Q6U8B1 
Go to UniProtKB:  Q6U8B1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ6U8B1
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.70 Å
  • R-Value Free: 0.215 
  • R-Value Work: 0.183 
  • R-Value Observed: 0.185 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 141.75α = 90
b = 53.55β = 125.77
c = 87.47γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2016-03-09
    Type: Initial release
  • Version 1.1: 2016-03-16
    Changes: Database references
  • Version 1.2: 2016-05-11
    Changes: Database references
  • Version 1.3: 2016-07-06
    Changes: Other
  • Version 1.4: 2024-03-06
    Changes: Data collection, Database references, Derived calculations