Related Experiment Video
Updated: Aug 10, 2026

In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa
Published on: February 17, 2014
Conformational flexibility in the multidrug efflux system protein AcrA
Jonathan Mikolosko1, Kostyantyn Bobyk, Helen I Zgurskaya
1Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92037, USA.
Abstract:
Intrinsic resistance to multiple drugs in many gram-negative bacterial pathogens is conferred by resistance nodulation cell division efflux pumps, which are composed of three essential components as typified by the extensively characterized Escherichia coli AcrA-AcrB-TolC system. The inner membrane drug:proton antiporter AcrB and the outer membrane channel TolC export chemically diverse compounds out of the bacterial cell, and require the activity of the third component, the periplasmic protein AcrA. The crystal structures of AcrB and TolC have previously been determined, and we complete the molecular picture of the efflux system by presenting the structure of a stable fragment of AcrA. The AcrA fragment resembles the elongated sickle shape of its homolog Pseudomonas aeruginosa MexA, being composed of three domains: beta-barrel, lipoyl, and alpha-helical hairpin. Notably, unsuspected conformational flexibility in the alpha-helical hairpin domain of AcrA is observed, which has potential mechanistic significance in coupling between AcrA conformations and TolC channel opening.
More Related Videos
05:06Characterizing Multidrug Efflux Systems in Acinetobacter baumannii Using an Efflux-Deficient Bacterial Strain and a Single-Copy Gene Expression System
Published on: January 5, 2024
07:31Native Cell Membrane Nanoparticles System for Membrane Protein-Protein Interaction Analysis
Published on: July 16, 2020
Related Concept Videos
ABC Transporters: Exporter
Carrier-Mediated Transport
Active transport involves two types of membrane-spanning transporters: uptake and efflux. Uptake transporters are expressed in the small...
The ADP/ATP Carrier Protein
ABC Transporters: Importer
In bacteria, based on the number of transmembrane helices and the chemical nature of their substrates, the ABC importers can be divided into three types:
Pharmacogenetics of Drug Transporters: P-Glycoprotein and Solute Carrier Transporters
Drug Absorption Mechanism: Carrier-Mediated Membrane Transport
Facilitated diffusion is a passive process that utilizes human Solute Carrier (SLC) transporters. These transporters bind to the drug, undergo structural...