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Updated: Feb 18, 2026

In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa
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In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa

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Dynamics of Intact MexAB-OprM Efflux Pump: Focusing on the MexA-OprM Interface

Cesar A López1, Timothy Travers1,2, Klaas M Pos3,4

  • 1Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, United States.

Scientific Reports
|November 30, 2017
PubMed

Insights

This study models the Pseudomonas aeruginosa MexAB-OprM efflux pump, revealing how its components interact to activate antibiotic expulsion. Understanding this mechanism is key to combating bacterial multidrug resistance.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Microbiology

Background:

  • Antibiotic efflux pumps are critical to bacterial multidrug resistance.
  • These pumps are complex, tripartite machines spanning bacterial membranes.
  • Understanding their assembly and dynamics is vital for new resistance-fighting strategies.

Purpose of the Study:

  • To build and analyze an atomistic model of the Pseudomonas aeruginosa MexAB-OprM efflux pump.
  • To investigate the stability and dynamics of the assembled pump.
  • To elucidate the interaction mechanism between MexA and OprM.

Main Methods:

  • All-atom and coarse-grained molecular dynamics (MD) simulations.
  • Construction of a Gram-negative membrane model with inner and outer membranes.
  • Sequence covariation analysis.

Main Results:

  • The intact MexAB-OprM pump model demonstrated stability over microsecond timescales.
  • Characterization of the MexA-OprM interface within the complete pump structure.
  • Identification of a plausible activation mechanism for OprM involving MexA-induced aperture opening.

Conclusions:

  • The study provides a stable, atomistic model of the MexAB-OprM efflux pump.
  • A detailed mechanism for OprM activation by MexA was proposed.
  • Findings offer insights for developing novel anti-resistance therapies.

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