1VF7

Crystal structure of the membrane fusion protein, MexA of the multidrug transporter


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.282 
  • R-Value Work: 0.258 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystal structure of the membrane fusion protein, MexA, of the multidrug transporter in Pseudomonas aeruginosa

Akama, H.Matsuura, T.Kashiwagi, S.Yoneyama, H.Narita, S.Tsukihara, T.Nakagawa, A.Nakae, T.

(2004) J.Biol.Chem. 279: 25939-25942

  • DOI: 10.1074/jbc.C400164200

  • PubMed Abstract: 
  • The MexAB-OprM efflux pump of Pseudomonas aeruginosa is central to multidrug resistance of this organism, which infects immunocompromised hospital patients. The MexA, MexB, and OprM subunits were assumed to function as the membrane fusion protein, th ...

    The MexAB-OprM efflux pump of Pseudomonas aeruginosa is central to multidrug resistance of this organism, which infects immunocompromised hospital patients. The MexA, MexB, and OprM subunits were assumed to function as the membrane fusion protein, the body of the transporter, and the outer membrane channel protein, respectively. For better understanding of this important xenobiotic transporter, we show the x-ray crystallographic structure of MexA at a resolution of 2.40 A. The global MexA structure showed unforeseen new features with a spiral assembly of six and seven protomers that were joined together at one end by a pseudo 2-fold image. The protomer showed a new protein structure with a tandem arrangement consisting of at least three domains and presumably one more. The rod domain had a long hairpin of twisted coiled-coil that extended to one end. The second domain adjacent to the rod alpha-helical domain was globular and constructed by a cluster of eight short beta-sheets. The third domain located distal to the alpha-helical rod was globular and composed of seven short beta-sheets and one short alpha-helix. The 13-mer was shaped like a woven rattan cylinder with a large internal tubular space and widely opened flared ends. The 6-mer and 7-mer had a funnel-like structure consisting of a tubular rod at one side and a widely opened flared funnel top at the other side. Based on these results, we constructed a model of the MexAB-OprM pump assembly. The three pairs of MexA dimers interacted with the periplasmic alpha-barrel domain of OprM via the alpha-helical hairpin, the second domain interacted with both MexB and OprM at their contact site, and the third and disordered domains probably interacted with the distal domain of MexB. In this fashion, the MexA subunit connected MexB and OprM, indicating that MexA is the membrane bridge protein.


    Organizational Affiliation

    Department of Molecular Life Science, Tokai University School of Medicine, Isehara, 259-1193, Japan.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Multidrug resistance protein mexA
A, B, C, D, E, F, G, H, I, J, K, L, M
369Pseudomonas aeruginosa (strain ATCC 15692 / PAO1 / 1C / PRS 101 / LMG 12228)Gene Names: mexA
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Multi-Drug Efflux Transporters
Protein: 
MexB bacterial multi-drug efflux transporter
Find proteins for P52477 (Pseudomonas aeruginosa (strain ATCC 15692 / PAO1 / 1C / PRS 101 / LMG 12228))
Go to UniProtKB:  P52477
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.282 
  • R-Value Work: 0.258 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 130.030α = 90.00
b = 180.350β = 106.99
c = 214.230γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
DENZOdata reduction
SHARPphasing
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-05-25
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance