Sequential mechanism of assembly of multidrug efflux pump AcrAB-TolC

Chem Biol. 2011 Apr 22;18(4):454-63. doi: 10.1016/j.chembiol.2011.02.011.


Multidrug efflux pumps adversely affect both the clinical effectiveness of existing antibiotics and the discovery process to find new ones. In this study, we reconstituted and characterized by surface plasmon resonance the assembly of AcrAB-TolC, the archetypal multidrug efflux pump from Escherichia coli. We report that the periplasmic AcrA and the outer membrane channel TolC assemble high-affinity complexes with AcrB transporter independently from each other. Antibiotic novobiocin and MC-207,110 inhibitor bind to the immobilized AcrB but do not affect interactions between components of the complex. In contrast, DARPin inhibits interactions between AcrA and AcrB. Mutational opening of TolC channel decreases stability of interactions and promotes disassembly of the complex. The conformation of the membrane proximal domain of AcrA is critical for the formation of AcrAB-TolC and could be targeted for the development of new inhibitors.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Bacterial Outer Membrane Proteins / antagonists & inhibitors
  • Bacterial Outer Membrane Proteins / chemistry
  • Bacterial Outer Membrane Proteins / genetics
  • Bacterial Outer Membrane Proteins / metabolism
  • Escherichia coli / cytology
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / antagonists & inhibitors
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • Immobilized Proteins / antagonists & inhibitors
  • Immobilized Proteins / chemistry
  • Immobilized Proteins / metabolism
  • Lipid Metabolism
  • Lipoproteins / antagonists & inhibitors
  • Lipoproteins / chemistry
  • Lipoproteins / metabolism
  • Membrane Transport Proteins / chemistry
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / metabolism
  • Models, Molecular
  • Multidrug Resistance-Associated Proteins / antagonists & inhibitors
  • Multidrug Resistance-Associated Proteins / chemistry
  • Multidrug Resistance-Associated Proteins / metabolism
  • Mutation
  • Protein Binding
  • Protein Conformation
  • Surface Plasmon Resonance


  • AcrA protein, E coli
  • AcrB protein, E coli
  • Bacterial Outer Membrane Proteins
  • Escherichia coli Proteins
  • Immobilized Proteins
  • Lipoproteins
  • Membrane Transport Proteins
  • Multidrug Resistance-Associated Proteins
  • tolC protein, E coli