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Expression, Detergent Solubilization, and Purification of a Membrane Transporter, the MexB Multidrug Resistance Protein
10:43

Expression, Detergent Solubilization, and Purification of a Membrane Transporter, the MexB Multidrug Resistance Protein

Published on: December 3, 2010

Promiscuous partnering and independent activity of MexB, the multidrug transporter protein from Pseudomonas

Alexander Welch1, Chidiebere U Awah, Shiheng Jing

  • 1Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, U.K.

The Biochemical Journal
|June 30, 2010
PubMed

Insights

The MexB protein, a key component of the MexAB-OprM efflux pump, can independently transport drugs. This finding challenges previous understanding of multidrug resistance in Pseudomonas aeruginosa.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Biochemistry

Background:

  • The MexAB-OprM efflux pump is crucial for multidrug resistance in Pseudomonas aeruginosa.
  • The exact roles of individual proteins in forming this complex are not fully understood.
  • A key question is whether MexB can function without MexA and OprM.

Purpose of the Study:

  • To investigate the independent function of the MexB protein.
  • To determine if MexB can form a functional drug efflux complex with heterologous proteins.
  • To assess MexB's ability to transport drugs in different cellular contexts.

Main Methods:

  • Recruitment of AcrA and TolC from Escherichia coli by MexB.
  • Assessing ethidium bromide transport in a Gram-positive organism.
  • Purifying and reconstituting MexB into proteoliposomes for drug transport assays.

Main Results:

  • MexB successfully recruited AcrA and TolC to form a functional efflux complex.
  • MexB demonstrated drug transport capabilities even in the absence of a periplasmic space and outer membrane.
  • Purified MexB catalyzed proton gradient-dependent drug transport.

Conclusions:

  • This study provides the first evidence of drug transport by an isolated resistance-nodulation-cell division (RND)-type multidrug transporter.
  • MexB can function independently of MexA and OprM.
  • These findings offer insights into the energetics and assembly of RND transporters.

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