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Updated: Apr 27, 2026

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

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Substrate binding to the multidrug transporter MepA

Christian Banchs1, Sandra Poulos1, Waroot S Nimjareansuk1

  • 1Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, 22903, United States.

Biochimica Et Biophysica Acta
|June 27, 2014
PubMed

Insights

MepA transporter

Area of Science:

  • Microbiology
  • Molecular Biology
  • Biochemistry

Background:

  • MepA from Staphylococcus aureus is a multidrug transporter.
  • It confers multidrug resistance by exporting hydrophobic substrates.
  • Understanding MepA's substrate recognition is crucial for combating antibiotic resistance.

Purpose of the Study:

  • To investigate the substrate binding characteristics of the MepA transporter.
  • To determine the dissociation constants (KD) for MepA with acriflavine, rhodamine 6G, and ethidium.
  • To assess the influence of detergent micelles on MepA-substrate interactions.

Main Methods:

  • Measurement of dissociation constants (KD) for MepA-substrate interactions.
  • Evaluation of substrate binding in the presence of varying detergent concentrations.
  • Analysis of the binding affinity of an inactive D183A mutant.

Main Results:

  • All tested substrates (acriflavine, rhodamine 6G, ethidium) interact with detergent micelles.
  • The effect of detergent on KD is substrate-specific: R6G affinity is highly affected, while Acr and Et are modestly affected.
  • The D183A mutant exhibited reduced binding affinity for acriflavine and ethidium.

Conclusions:

  • Detergent micelles significantly influence the measured binding affinities of MepA substrates.
  • MepA's substrate recognition mechanism is complex and affected by the experimental environment.
  • The D183A mutation impacts MepA's ability to bind certain substrates, providing insights into its active site.
Keywords:
Detergent effectDrug designDrug resistanceEffluxMembrane proteins

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