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Updated: Aug 20, 2026

In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa
Published on: February 17, 2014
A model of a transmembrane drug-efflux pump from Gram-negative bacteria
Juan Fernandez-Recio1, Fabien Walas, Luca Federici
1Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK.
Abstract:
In Gram-negative bacteria, drug resistance is due in part to the activity of transmembrane efflux-pumps, which are composed of three types of proteins. A representative pump from Escherichia coli is an assembly of the trimeric outer-membrane protein TolC, which is an allosteric channel, the trimeric inner-membrane proton-antiporter AcrB, and the periplasmic protein, AcrA. The pump displaces drugs vectorially from the bacterium using proton electrochemical force. Crystal structures are available for TolC and AcrB from E. coli, and for the AcrA homologue MexA from Pseudomonas aeruginosa. Based on homology modelling and molecular docking, we show how AcrA, AcrB and TolC might assemble to form a tripartite pump, and how allostery may occur during transport.
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