The Missing Part of the Bacterial MexAB-OprM System: Structural determination of the Multidrug Exporter MexB

Experimental Data Snapshot

  • Resolution: 3.00 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.242 
  • R-Value Observed: 0.243 

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Crystal Structure of the Multidrug Exporter Mexb from Pseudomonas Aeruginosa.

Sennhauser, G.Bukowska, M.A.Briand, C.Gruetter, M.G.

(2009) J Mol Biol 389: 134

  • DOI: https://doi.org/10.1016/j.jmb.2009.04.001
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    We report here the crystal structure of the Pseudomonas aeruginosa multidrug exporter MexB, an intensively studied member of the resistance-nodulation-cell division family of secondary active transporters, at 3.0 A. MexB forms an asymmetric homotrimer where each subunit adopts a different conformation representing three snapshots of the transport cycle similar to the recently determined structures of its close homologue AcrB from Escherichia coli, so far the sole structurally characterized member of the superfamily. As for AcrB, the conformations of two subunits can be clearly assigned to either the binding step or the extrusion step in the transport process. Unexpectedly, a remarkable conformational shift in the third subunit is observed in MexB, which has potential implications for the assembly of the tripartite MexAB-OprM drug efflux system. Furthermore, an n-dodecyl-d-maltoside molecule was found bound to the internal multidrug-binding cavity, which might indicate that MexB binds and transports detergent molecules as substrates. As the only missing piece of the puzzle in the MexAB-OprM system, the X-ray structure of MexB completes the molecular picture of the major pump mediating intrinsic and acquired multidrug resistance in P. aeruginosa.

  • Organizational Affiliation

    Department of Biochemistry, University of Zurich, Switzerland.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C, D, E
A, B, C, D, E, F
1,052Pseudomonas aeruginosa PAO1Mutation(s): 0 
Membrane Entity: Yes 
Find proteins for P52002 (Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1))
Explore P52002 
Go to UniProtKB:  P52002
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP52002
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.00 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.242 
  • R-Value Observed: 0.243 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 125.05α = 86.99
b = 134.58β = 69.7
c = 151.02γ = 88.16
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: 2009-05-19
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-01-24
    Changes: Advisory, Source and taxonomy
  • Version 1.4: 2023-12-13
    Changes: Advisory, Data collection, Database references, Derived calculations, Other, Refinement description